diff --git a/src/RA_AchievementOverlay.cpp b/src/RA_AchievementOverlay.cpp
index c1e8784d1..4868d5d19 100644
--- a/src/RA_AchievementOverlay.cpp
+++ b/src/RA_AchievementOverlay.cpp
@@ -130,7 +130,7 @@ void AchievementOverlay::Initialize(HINSTANCE hInst)
 
     m_LatestNews.clear();
 
-    m_hOverlayBackground.ChangeReference(ra::services::ImageType::Local, RA_DIR_OVERLAY "overlayBG.png");
+    m_hOverlayBackground.ChangeReference(ra::services::ImageType::Local, "Overlay\\overlayBG.png");
     m_hUserImage.ChangeReference(ra::services::ImageType::UserPic, RAUsers::LocalUser().Username());
 }
 
@@ -1506,9 +1506,9 @@ void AchievementOverlay::InstallNewsArticlesFromFile()
 {
     m_LatestNews.clear();
 
-    std::string sNewsFile = g_sHomeDir + RA_NEWS_FILENAME;
+    std::wstring sNewsFile = g_sHomeDir + RA_NEWS_FILENAME;
     FILE* pf = nullptr;
-    fopen_s(&pf, sNewsFile.c_str(), "rb");
+    _wfopen_s(&pf, sNewsFile.c_str(), L"rb");
     if (pf != nullptr)
     {
         Document doc;
diff --git a/src/RA_AchievementPopup.cpp b/src/RA_AchievementPopup.cpp
index cbde6b5ef..ecb510b0c 100644
--- a/src/RA_AchievementPopup.cpp
+++ b/src/RA_AchievementPopup.cpp
@@ -22,15 +22,15 @@ const float APPEAR_AT = 0.8f;
 const float FADEOUT_AT = 4.2f;
 const float FINISH_AT = 5.0f;
 
-const char* MSG_SOUND[] =
+const wchar_t* MSG_SOUND[] =
 {
-    "login.wav",
-    "info.wav",
-    "unlock.wav",
-    "acherror.wav",
-    "lb.wav",
-    "lbcancel.wav",
-    "message.wav",
+    L"login.wav",
+    L"info.wav",
+    L"unlock.wav",
+    L"acherror.wav",
+    L"lb.wav",
+    L"lbcancel.wav",
+    L"message.wav",
 };
 static_assert(SIZEOF_ARRAY(MSG_SOUND) == NumMessageTypes, "Must match!");
 }
@@ -43,8 +43,8 @@ AchievementPopup::AchievementPopup() :
 void AchievementPopup::PlayAudio()
 {
     ASSERT(MessagesPresent());	//	ActiveMessage() dereferences!
-    std::string sSoundPath = g_sHomeDir + RA_DIR_OVERLAY + MSG_SOUND[ActiveMessage().Type()];
-    PlaySoundA(sSoundPath.c_str(), nullptr, SND_FILENAME | SND_ASYNC);
+    std::wstring sSoundPath = g_sHomeDir + RA_DIR_OVERLAY + MSG_SOUND[ActiveMessage().Type()];
+    PlaySoundW(sSoundPath.c_str(), nullptr, SND_FILENAME | SND_ASYNC);
 }
 
 void AchievementPopup::AddMessage(const MessagePopup& msg)
diff --git a/src/RA_AchievementSet.cpp b/src/RA_AchievementSet.cpp
index fa38ce844..5983eceff 100644
--- a/src/RA_AchievementSet.cpp
+++ b/src/RA_AchievementSet.cpp
@@ -29,18 +29,18 @@ void RASetAchievementCollection(AchievementSetType Type)
     g_pActiveAchievements = *ACH_SETS[Type];
 }
 
-std::string AchievementSet::GetAchievementSetFilename(ra::GameID nGameID)
+std::wstring AchievementSet::GetAchievementSetFilename(ra::GameID nGameID)
 {
     switch (m_nSetType)
     {
         case Core:
-            return g_sHomeDir + RA_DIR_DATA + std::to_string(nGameID) + ".txt";
+            return g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L".txt";
         case Unofficial:
-            return g_sHomeDir + RA_DIR_DATA + std::to_string(nGameID) + ".txt";	// Same as Core
+            return g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L".txt";	// Same as Core
         case Local:
-            return g_sHomeDir + RA_DIR_DATA + std::to_string(nGameID) + "-User.txt";
+            return g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L"-User.txt";
         default:
-            return "";
+            return L"";
     }
 }
 
@@ -59,8 +59,8 @@ BOOL AchievementSet::DeletePatchFile(ra::GameID nGameID)
     }
 
     //	Remove the text file
-    std::string sFilename = GetAchievementSetFilename(nGameID);
-    return RemoveFileIfExists(g_sHomeDir + "\\" + sFilename);
+    std::wstring sFilename = GetAchievementSetFilename(nGameID);
+    return RemoveFileIfExists(g_sHomeDir + L"\\" + sFilename);
 }
 
 //static 
@@ -267,9 +267,9 @@ BOOL AchievementSet::SaveToFile()
     char sMem[2048];
     unsigned int i = 0;
 
-    const std::string sFilename = GetAchievementSetFilename(g_pCurrentGameData->GetGameID());
+    const std::wstring sFilename = GetAchievementSetFilename(g_pCurrentGameData->GetGameID());
 
-    fopen_s(&pFile, sFilename.c_str(), "w");
+    _wfopen_s(&pFile, sFilename.c_str(), L"w");
     if (pFile != nullptr)
     {
         sprintf_s(sNextLine, 2048, "0.030\n");						//	Min ver
@@ -399,7 +399,7 @@ BOOL AchievementSet::FetchFromWebBlocking(ra::GameID nGameID)
     {
         const Value& PatchData = doc["PatchData"];
         FILE* pf = nullptr;
-        fopen_s(&pf, std::string(g_sHomeDir + RA_DIR_DATA + std::to_string(nGameID) + ".txt").c_str(), "wb");
+        _wfopen_s(&pf, std::wstring(g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L".txt").c_str(), L"wb");
         if (pf != nullptr)
         {
             FileStream fs(pf);
@@ -435,10 +435,10 @@ BOOL AchievementSet::LoadFromFile(ra::GameID nGameID)
         return TRUE;
     }
 
-    const std::string sFilename = GetAchievementSetFilename(nGameID);
+    const std::wstring sFilename = GetAchievementSetFilename(nGameID);
 
     FILE* pFile = nullptr;
-    errno_t nErr = fopen_s(&pFile, sFilename.c_str(), "r");
+    errno_t nErr = _wfopen_s(&pFile, sFilename.c_str(), L"r");
     if (pFile != nullptr)
     {
         //	Store this: we are now assuming this is the correct checksum if we have a file for it
@@ -502,7 +502,7 @@ BOOL AchievementSet::LoadFromFile(ra::GameID nGameID)
                 ra::GameID nGameID = g_pCurrentGameData->GetGameID();
 
                 //	Rich Presence
-                _WriteBufferToFile(g_sHomeDir + RA_DIR_DATA + std::to_string(nGameID) + "-Rich.txt", g_pCurrentGameData->RichPresencePatch());
+                _WriteBufferToFile(g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L"-Rich.txt", g_pCurrentGameData->RichPresencePatch());
                 g_RichPresenceInterpreter.ParseFromString(g_pCurrentGameData->RichPresencePatch().c_str());
 
                 const Value& AchievementsData = doc["Achievements"];
@@ -603,10 +603,9 @@ void AchievementSet::SaveProgress(const char* sSaveStateFilename)
     if (sSaveStateFilename == nullptr)
         return;
 
-    char buffer[4096];
-    sprintf_s(buffer, 4096, "%s.rap", sSaveStateFilename);
+    std::wstring sAchievementStateFile = ra::Widen(sSaveStateFilename) + L".rap";
     FILE* pf = nullptr;
-    fopen_s(&pf, buffer, "w");
+    _wfopen_s(&pf, sAchievementStateFile.c_str(), L"w");
     if (pf == nullptr)
     {
         ASSERT(!"Could not save progress!");
@@ -628,7 +627,6 @@ void AchievementSet::SaveProgress(const char* sSaveStateFilename)
 
 void AchievementSet::LoadProgress(const char* sLoadStateFilename)
 {
-    char buffer[4096];
     long nFileSize;
 
     if (!RAUsers::LocalUser().IsLoggedIn())
@@ -637,9 +635,9 @@ void AchievementSet::LoadProgress(const char* sLoadStateFilename)
     if (sLoadStateFilename == nullptr)
         return;
 
-    sprintf_s(buffer, sizeof(buffer), "%s.rap", sLoadStateFilename);
+    std::wstring sAchievementStateFile = ra::Widen(sLoadStateFilename) + L".rap";
 
-    char* pRawFile = _MallocAndBulkReadFileToBuffer(buffer, nFileSize);
+    char* pRawFile = _MallocAndBulkReadFileToBuffer(sAchievementStateFile.c_str(), nFileSize);
     if (pRawFile != nullptr)
     {
         const char* pIter = pRawFile;
diff --git a/src/RA_AchievementSet.h b/src/RA_AchievementSet.h
index eb63d815a..a1928a724 100644
--- a/src/RA_AchievementSet.h
+++ b/src/RA_AchievementSet.h
@@ -34,7 +34,7 @@ class AchievementSet
 
     BOOL DeletePatchFile(ra::GameID nGameID);
 
-    std::string GetAchievementSetFilename(ra::GameID nGameID);
+    std::wstring GetAchievementSetFilename(ra::GameID nGameID);
 
     //	Get Achievement at offset
     Achievement& GetAchievement(size_t nIter) { return m_Achievements[nIter]; }
diff --git a/src/RA_CodeNotes.cpp b/src/RA_CodeNotes.cpp
index bc9f38477..7cf7af2e9 100644
--- a/src/RA_CodeNotes.cpp
+++ b/src/RA_CodeNotes.cpp
@@ -12,12 +12,12 @@ void CodeNotes::Clear()
     m_CodeNotes.clear();
 }
 
-size_t CodeNotes::Load(const std::string& sFile)
+size_t CodeNotes::Load(const std::wstring& sFile)
 {
     Clear();
 
     FILE* pf = nullptr;
-    if (fopen_s(&pf, sFile.c_str(), "rb") == 0)
+    if (_wfopen_s(&pf, sFile.c_str(), L"rb") == 0)
     {
         Document doc;
         doc.ParseStream(FileStream(pf));
@@ -50,7 +50,7 @@ size_t CodeNotes::Load(const std::string& sFile)
     return m_CodeNotes.size();
 }
 
-BOOL CodeNotes::Save(const std::string& sFile)
+BOOL CodeNotes::Save(const std::wstring& sFile)
 {
     return FALSE;
     //	All saving should be cloud-based!
@@ -73,7 +73,7 @@ void CodeNotes::OnCodeNotesResponse(Document& doc)
     //	Persist then reload
     const ra::GameID nGameID = doc["GameID"].GetUint();
 
-    _WriteBufferToFile(g_sHomeDir + std::string(RA_DIR_DATA) + std::to_string(nGameID) + "-Notes2.txt", doc);
+    _WriteBufferToFile(g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L"-Notes2.txt", doc);
 
     g_MemoryDialog.RepopulateMemNotesFromFile();
 }
diff --git a/src/RA_CodeNotes.h b/src/RA_CodeNotes.h
index 57f2a0b7f..80affa8cb 100644
--- a/src/RA_CodeNotes.h
+++ b/src/RA_CodeNotes.h
@@ -29,8 +29,8 @@ class CodeNotes
 public:
     void Clear();
 
-    BOOL Save(const std::string& sFile);
-    size_t Load(const std::string& sFile);
+    BOOL Save(const std::wstring& sFile);
+    size_t Load(const std::wstring& sFile);
 
     BOOL ReloadFromWeb(ra::GameID nID);
     static void OnCodeNotesResponse(Document& doc);
diff --git a/src/RA_Core.cpp b/src/RA_Core.cpp
index bbbe05afd..bbec728f3 100644
--- a/src/RA_Core.cpp
+++ b/src/RA_Core.cpp
@@ -42,7 +42,7 @@
 #endif // WIN32_LEAN_AND_MEAN
 
 std::string g_sKnownRAVersion;
-std::string g_sHomeDir;
+std::wstring g_sHomeDir;
 std::string g_sROMDirLocation;
 std::string g_sCurrentROMMD5;	//	Internal
 
@@ -112,23 +112,24 @@ API const char* CCONV _RA_HostName()
     return sHostName.c_str();
 }
 
-static void EnsureDirectoryExists(const std::string& sDirectory)
+static void EnsureDirectoryExists(const std::wstring& sDirectory)
 {
-    if (DirectoryExists(sDirectory.c_str()) == FALSE)
-        _mkdir(sDirectory.c_str());
+    DWORD nAttrib = GetFileAttributesW(sDirectory.c_str());
+    if (nAttrib == INVALID_FILE_ATTRIBUTES)
+        CreateDirectoryW(sDirectory.c_str(), nullptr);
 }
 
 static void InitCommon(HWND hMainHWND, /*enum EmulatorID*/int nEmulatorID, const char* sClientVer)
 {
     // determine the home directory from the executable's path
-    TCHAR sBuffer[MAX_PATH];
-    GetModuleFileName(0, sBuffer, MAX_PATH);
-    PathRemoveFileSpec(sBuffer);
-    g_sHomeDir = ra::Narrow(sBuffer);
+    wchar_t sBuffer[MAX_PATH];
+    GetModuleFileNameW(0, sBuffer, MAX_PATH);
+    PathRemoveFileSpecW(sBuffer);
+    g_sHomeDir = sBuffer;
     if (g_sHomeDir.back() != '\\')
         g_sHomeDir.push_back('\\');
 
-    RA_LOG(__FUNCTION__ " - storing \"%s\" as home dir\n", g_sHomeDir.c_str());
+    RA_LOG(__FUNCTION__ " - storing \"%s\" as home dir\n", ra::Narrow(g_sHomeDir).c_str());
 
     //	Ensure all required directories are created:
     EnsureDirectoryExists(g_sHomeDir + RA_DIR_BASE);
@@ -654,7 +655,7 @@ API int CCONV _RA_HandleHTTPResults()
                 case RequestBadge:
                 {
                     const std::string& sBadgeURI = pObj->GetData();
-                    _WriteBufferToFile(g_sHomeDir + RA_DIR_BADGE + sBadgeURI + ".png", pObj->GetResponse());
+                    _WriteBufferToFile(g_sHomeDir + RA_DIR_BADGE + ra::Widen(sBadgeURI) + L".png", pObj->GetResponse());
 
                     /* This block seems unnecessary. --GD
                     for( size_t i = 0; i < g_pActiveAchievements->NumAchievements(); ++i )
@@ -679,7 +680,7 @@ API int CCONV _RA_HandleHTTPResults()
                 case RequestUserPic:
                 {
                     const std::string& sUsername = pObj->GetData();
-                    _WriteBufferToFile(g_sHomeDir + RA_DIR_USERPIC + sUsername + ".png", pObj->GetResponse());
+                    _WriteBufferToFile(g_sHomeDir + RA_DIR_USERPIC + ra::Widen(sUsername) + L".png", pObj->GetResponse());
                     break;
                 }
 
@@ -956,9 +957,9 @@ API void CCONV _RA_LoadPreferences()
 {
     RA_LOG(__FUNCTION__ " - loading preferences...\n");
 
-    std::string sPreferencesFile = g_sHomeDir + RA_PREFERENCES_FILENAME_PREFIX + g_sClientName + ".cfg";
+    std::wstring sPreferencesFile = g_sHomeDir + RA_PREFERENCES_FILENAME_PREFIX + ra::Widen(g_sClientName) + L".cfg";
     FILE* pf = nullptr;
-    fopen_s(&pf, sPreferencesFile.c_str(), "rb");
+    _wfopen_s(&pf, sPreferencesFile.c_str(), L"rb");
     if (pf == nullptr)
     {
         //	Test for first-time use:
@@ -1081,9 +1082,9 @@ API void CCONV _RA_SavePreferences()
         return;
     }
 
-    std::string sPreferencesFile = g_sHomeDir + RA_PREFERENCES_FILENAME_PREFIX + g_sClientName + ".cfg";
+    std::wstring sPreferencesFile = g_sHomeDir + RA_PREFERENCES_FILENAME_PREFIX + ra::Widen(g_sClientName) + L".cfg";
     FILE* pf = nullptr;
-    fopen_s(&pf, sPreferencesFile.c_str(), "wb");
+    _wfopen_s(&pf, sPreferencesFile.c_str(), L"wb");
     if (pf != nullptr)
     {
         FileStream fs(pf);
@@ -1419,11 +1420,10 @@ API void CCONV _RA_InvokeDialog(LPARAM nID)
 
         case IDM_RA_PARSERICHPRESENCE:
         {
-            char sRichPresenceFile[1024];
-            sprintf_s(sRichPresenceFile, 1024, "%s%s%u-Rich.txt", g_sHomeDir.c_str(), RA_DIR_DATA, g_pCurrentGameData->GetGameID());
+            std::wstring sRichPresenceFile = g_sHomeDir + RA_DIR_DATA + std::to_wstring(g_pCurrentGameData->GetGameID()) + L"-Rich.txt";
 
             std::string sRichPresence;
-            bool bRichPresenceExists = _ReadBufferFromFile(sRichPresence, sRichPresenceFile);
+            bool bRichPresenceExists = _ReadBufferFromFile(sRichPresence, sRichPresenceFile.c_str());
             g_RichPresenceInterpreter.ParseFromString(sRichPresence.c_str());
 
             if (g_RichPresenceDialog.GetHWND() == nullptr)
@@ -1553,11 +1553,6 @@ void CCONV _RA_InstallSharedFunctionsExt(bool(*fpIsActive)(void), void(*fpCauseU
     _RA_LoadROM = fpLoadROM;
 }
 
-API bool _RA_UserLoggedIn()
-{
-    return(RAUsers::LocalUser().IsLoggedIn() == TRUE);
-}
-
 
 //////////////////////////////////////////////////////////////////////////
 
@@ -1606,10 +1601,10 @@ void _ReadStringTil(std::string& value, char nChar, const char*& pSource)
     pSource++;
 }
 
-void _WriteBufferToFile(const std::string& sFileName, const Document& doc)
+void _WriteBufferToFile(const std::wstring& sFileName, const Document& doc)
 {
     FILE* pf = nullptr;
-    if (fopen_s(&pf, sFileName.c_str(), "wb") == 0)
+    if (_wfopen_s(&pf, sFileName.c_str(), L"wb") == 0)
     {
         FileStream fs(pf);
         Writer<FileStream> writer(fs);
@@ -1618,18 +1613,18 @@ void _WriteBufferToFile(const std::string& sFileName, const Document& doc)
     }
 }
 
-void _WriteBufferToFile(const std::string& sFileName, const std::string& raw)
+void _WriteBufferToFile(const std::wstring& sFileName, const std::string& raw)
 {
     using FileH = std::unique_ptr<FILE, decltype(&std::fclose)>;
 #pragma warning(push)
 #pragma warning(disable : 4996) // Deprecation from Microsoft
-    FileH myFile{ std::fopen(sFileName.c_str(), "wb"), std::fclose };
+    FileH myFile{ _wfopen(sFileName.c_str(), L"wb"), std::fclose };
 #pragma warning(pop)
 
     std::fwrite(static_cast<const void*>(raw.c_str()), sizeof(char), raw.length(), myFile.get());
 }
 
-bool _ReadBufferFromFile(_Out_ std::string& buffer, const char* sFile)
+bool _ReadBufferFromFile(_Out_ std::string& buffer, const wchar_t* sFile)
 {
     std::ifstream file(sFile);
     if (file.fail())
@@ -1644,10 +1639,10 @@ bool _ReadBufferFromFile(_Out_ std::string& buffer, const char* sFile)
     return true;
 }
 
-char* _MallocAndBulkReadFileToBuffer(const char* sFilename, long& nFileSizeOut)
+char* _MallocAndBulkReadFileToBuffer(const wchar_t* sFilename, long& nFileSizeOut)
 {
     FILE* pf = nullptr;
-    fopen_s(&pf, sFilename, "r");
+    _wfopen_s(&pf, sFilename, L"r");
     if (pf == nullptr)
         return nullptr;
 
@@ -1681,10 +1676,10 @@ std::string _TimeStampToString(time_t nTime)
     return std::string(buffer);
 }
 
-BOOL _FileExists(const std::string& sFileName)
+BOOL _FileExists(const std::wstring& sFileName)
 {
     FILE* pf = nullptr;
-    fopen_s(&pf, sFileName.c_str(), "rb");
+    _wfopen_s(&pf, sFileName.c_str(), L"rb");
     if (pf != nullptr)
     {
         fclose(pf);
@@ -1726,11 +1721,11 @@ std::string GetFolderFromDialog()
     return sRetVal;
 }
 
-BOOL RemoveFileIfExists(const std::string& sFilePath)
+BOOL RemoveFileIfExists(const std::wstring& sFilePath)
 {
-    if (_access(sFilePath.c_str(), 06) != -1)	//	06= Read/write permission
+    if (_waccess(sFilePath.c_str(), 06) != -1)	//	06= Read/write permission
     {
-        if (remove(sFilePath.c_str()) == -1)
+        if (_wremove(sFilePath.c_str()) == -1)
         {
             //	Remove issues?
             ASSERT(!"Could not remove patch file!?");
diff --git a/src/RA_Core.h b/src/RA_Core.h
index 8b66b0596..0020c1015 100644
--- a/src/RA_Core.h
+++ b/src/RA_Core.h
@@ -105,7 +105,7 @@ extern "C" {
 
 //	Non-exposed:
 extern std::string g_sKnownRAVersion;
-extern std::string g_sHomeDir;
+extern std::wstring g_sHomeDir;
 extern std::string g_sROMDirLocation;
 extern std::string g_sCurrentROMMD5;
 
@@ -127,10 +127,10 @@ extern bool g_bPreferDecimalVal;
 extern unsigned int g_nNumHTTPThreads;
 
 //	Read a file to a malloc'd buffer. Returns nullptr on error. Owner MUST free() buffer if not nullptr.
-extern char* _MallocAndBulkReadFileToBuffer(const char* sFilename, long& nFileSizeOut);
+extern char* _MallocAndBulkReadFileToBuffer(const wchar_t* sFilename, long& nFileSizeOut);
 
 //  Read a file to a std::string. Returns false on error.
-extern bool _ReadBufferFromFile(_Out_ std::string& buffer, const char* sFile);
+extern bool _ReadBufferFromFile(_Out_ std::string& buffer, const wchar_t* sFile);
 
 //	Read file until reaching the end of the file, or the specified char.
 extern BOOL _ReadTil(const char nChar, char buffer[], unsigned int nSize, DWORD* pCharsRead, FILE* pFile);
@@ -140,8 +140,8 @@ extern char* _ReadStringTil(char nChar, char*& pOffsetInOut, BOOL bTerminate);
 extern void  _ReadStringTil(std::string& sValue, char nChar, const char*& pOffsetInOut);
 
 //	Write out the buffer to a file
-extern void _WriteBufferToFile(const std::string& sFileName, const std::string& sString);
-extern void _WriteBufferToFile(const std::string& sFileName, const Document& doc);
+extern void _WriteBufferToFile(const std::wstring& sFileName, const std::string& sString);
+extern void _WriteBufferToFile(const std::wstring& sFileName, const Document& doc);
 
 //	Fetch various interim txt/data files
 extern void _FetchGameHashLibraryFromWeb();
@@ -149,14 +149,14 @@ extern void _FetchGameTitlesFromWeb();
 extern void _FetchMyProgressFromWeb();
 
 
-extern BOOL _FileExists(const std::string& sFileName);
+extern BOOL _FileExists(const std::wstring& sFileName);
 
 extern std::string _TimeStampToString(time_t nTime);
 
 
 extern std::string GetFolderFromDialog();
 
-extern BOOL RemoveFileIfExists(const std::string& sFilePath);
+extern BOOL RemoveFileIfExists(const std::wstring& sFilePath);
 
 BOOL CanCausePause();
 
diff --git a/src/RA_Defs.cpp b/src/RA_Defs.cpp
index 3bc8d8df6..e4e8bf541 100644
--- a/src/RA_Defs.cpp
+++ b/src/RA_Defs.cpp
@@ -53,7 +53,7 @@ _Use_decl_annotations_ std::wstring Widen(std::string&& str) noexcept
 _Use_decl_annotations_ std::wstring Widen(const char* str)
 {
     auto len{ ra::to_signed(std::strlen(str)) };
-    auto needed{::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str, len + 1, nullptr, 0)};
+    auto needed{::MultiByteToWideChar(CP_UTF8, 0, str, len + 1, nullptr, 0)};
     // doesn't seem wchar_t is treated like a character type by default
     std::wstring wstr(ra::to_unsigned(needed), L'\x0'); 
     ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str, len + 1, wstr.data(),
@@ -97,7 +97,7 @@ _Use_decl_annotations_ std::string Narrow(const std::string& str)
 } // namespace ra
 
 #ifndef RA_UTEST
-extern std::string g_sHomeDir;
+extern std::wstring g_sHomeDir;
 #endif
 
 void RADebugLogNoFormat(const char* data)
@@ -105,9 +105,9 @@ void RADebugLogNoFormat(const char* data)
     OutputDebugString(NativeStr(data).c_str());
 
 #ifndef RA_UTEST
-    std::string sLogFile = g_sHomeDir + RA_LOG_FILENAME;
+    std::wstring sLogFile = g_sHomeDir + RA_LOG_FILENAME;
     FILE* pf = nullptr;
-    if (fopen_s(&pf, sLogFile.c_str(), "a") == 0)
+    if (_wfopen_s(&pf, sLogFile.c_str(), L"a") == 0)
     {
         fwrite(data, sizeof(char), strlen(data), pf);
         fclose(pf);
diff --git a/src/RA_Defs.h b/src/RA_Defs.h
index e3906d694..6180a1959 100644
--- a/src/RA_Defs.h
+++ b/src/RA_Defs.h
@@ -138,23 +138,23 @@ using namespace std::string_literals;
 #define _CONSTANT_FN  _CONSTANT_VAR
 
 #define RA_KEYS_DLL						"RA_Keys.dll"
-#define RA_PREFERENCES_FILENAME_PREFIX	"RAPrefs_"
-
-#define RA_DIR_OVERLAY					"Overlay\\"
-#define RA_DIR_BASE						"RACache\\"
-#define RA_DIR_DATA						RA_DIR_BASE##"Data\\"
-#define RA_DIR_BADGE					RA_DIR_BASE##"Badge\\"
-#define RA_DIR_USERPIC					RA_DIR_BASE##"UserPic\\"
-#define RA_DIR_BOOKMARKS				RA_DIR_BASE##"Bookmarks\\"
-
-#define RA_GAME_HASH_FILENAME			RA_DIR_DATA##"gamehashlibrary.txt"
-#define RA_GAME_LIST_FILENAME			RA_DIR_DATA##"gametitles.txt"
-#define RA_MY_PROGRESS_FILENAME			RA_DIR_DATA##"myprogress.txt"
-#define RA_MY_GAME_LIBRARY_FILENAME		RA_DIR_DATA##"mygamelibrary.txt"
-
-#define RA_NEWS_FILENAME				RA_DIR_DATA##"ra_news.txt"
-#define RA_TITLES_FILENAME				RA_DIR_DATA##"gametitles.txt"
-#define RA_LOG_FILENAME					RA_DIR_DATA##"RALog.txt"
+#define RA_PREFERENCES_FILENAME_PREFIX	L"RAPrefs_"
+
+#define RA_DIR_OVERLAY					L"Overlay\\"
+#define RA_DIR_BASE						L"RACache\\"
+#define RA_DIR_DATA						RA_DIR_BASE L"Data\\"
+#define RA_DIR_BADGE					RA_DIR_BASE L"Badge\\"
+#define RA_DIR_USERPIC					RA_DIR_BASE L"UserPic\\"
+#define RA_DIR_BOOKMARKS				RA_DIR_BASE L"Bookmarks\\"
+
+#define RA_GAME_HASH_FILENAME			RA_DIR_DATA L"gamehashlibrary.txt"
+#define RA_GAME_LIST_FILENAME			RA_DIR_DATA L"gametitles.txt"
+#define RA_MY_PROGRESS_FILENAME			RA_DIR_DATA L"myprogress.txt"
+#define RA_MY_GAME_LIBRARY_FILENAME		RA_DIR_DATA L"mygamelibrary.txt"
+
+#define RA_NEWS_FILENAME				RA_DIR_DATA L"ra_news.txt"
+#define RA_TITLES_FILENAME				RA_DIR_DATA L"gametitles.txt"
+#define RA_LOG_FILENAME					RA_DIR_DATA L"RALog.txt"
 
 
 #define SIZEOF_ARRAY( ar )	( sizeof( ar ) / sizeof( ar[ 0 ] ) )
diff --git a/src/RA_Dlg_GameLibrary.cpp b/src/RA_Dlg_GameLibrary.cpp
index d01b27866..394f56269 100644
--- a/src/RA_Dlg_GameLibrary.cpp
+++ b/src/RA_Dlg_GameLibrary.cpp
@@ -91,9 +91,9 @@ Dlg_GameLibrary::~Dlg_GameLibrary()
 
 void ParseGameHashLibraryFromFile(std::map<std::string, ra::GameID>& GameHashLibraryOut)
 {
-    std::string sGameHashFile = g_sHomeDir + RA_GAME_HASH_FILENAME;
+    std::wstring sGameHashFile = g_sHomeDir + RA_GAME_HASH_FILENAME;
     FILE* pf = nullptr;
-    fopen_s(&pf, sGameHashFile.c_str(), "rb");
+    _wfopen_s(&pf, sGameHashFile.c_str(), L"rb");
     if (pf != nullptr)
     {
         Document doc;
@@ -120,9 +120,9 @@ void ParseGameHashLibraryFromFile(std::map<std::string, ra::GameID>& GameHashLib
 
 void ParseGameTitlesFromFile(std::map<ra::GameID, std::string>& GameTitlesListOut)
 {
-    std::string sTitlesFile = g_sHomeDir + RA_TITLES_FILENAME;
+    std::wstring sTitlesFile = g_sHomeDir + RA_TITLES_FILENAME;
     FILE* pf = nullptr;
-    fopen_s(&pf, sTitlesFile.c_str(), "rb");
+    _wfopen_s(&pf, sTitlesFile.c_str(), L"rb");
     if (pf != nullptr)
     {
         Document doc;
@@ -148,9 +148,9 @@ void ParseGameTitlesFromFile(std::map<ra::GameID, std::string>& GameTitlesListOu
 
 void ParseMyProgressFromFile(std::map<ra::GameID, std::string>& GameProgressOut)
 {
-    std::string sProgressFile = g_sHomeDir + RA_TITLES_FILENAME;
+    std::wstring sProgressFile = g_sHomeDir + RA_TITLES_FILENAME;
     FILE* pf = nullptr;
-    fopen_s(&pf, sProgressFile.c_str(), "rb");
+    _wfopen_s(&pf, sProgressFile.c_str(), L"rb");
     if (pf != nullptr)
     {
         Document doc;
@@ -469,11 +469,11 @@ BOOL Dlg_GameLibrary::LaunchSelected()
 
 void Dlg_GameLibrary::LoadAll()
 {
-    std::string sMyGameLibraryFile = g_sHomeDir + RA_MY_GAME_LIBRARY_FILENAME;
+    std::wstring sMyGameLibraryFile = g_sHomeDir + RA_MY_GAME_LIBRARY_FILENAME;
     
     mtx.lock();
     FILE* pLoadIn = nullptr;
-    fopen_s(&pLoadIn, sMyGameLibraryFile.c_str(), "rb");
+    _wfopen_s(&pLoadIn, sMyGameLibraryFile.c_str(), L"rb");
     if (pLoadIn != nullptr)
     {
         DWORD nCharsRead1 = 0;
@@ -513,11 +513,11 @@ void Dlg_GameLibrary::LoadAll()
 
 void Dlg_GameLibrary::SaveAll()
 {
-    std::string sMyGameLibraryFile = g_sHomeDir + RA_MY_GAME_LIBRARY_FILENAME;
+    std::wstring sMyGameLibraryFile = g_sHomeDir + RA_MY_GAME_LIBRARY_FILENAME;
 
     mtx.lock();
     FILE* pf = nullptr;
-    fopen_s(&pf, sMyGameLibraryFile.c_str(), "wb");
+    _wfopen_s(&pf, sMyGameLibraryFile.c_str(), L"wb");
     if (pf != nullptr)
     {
         std::map<std::string, std::string>::iterator iter = Results.begin();
diff --git a/src/RA_Dlg_MemBookmark.cpp b/src/RA_Dlg_MemBookmark.cpp
index 57d40846c..956287b34 100644
--- a/src/RA_Dlg_MemBookmark.cpp
+++ b/src/RA_Dlg_MemBookmark.cpp
@@ -119,7 +119,7 @@ INT_PTR Dlg_MemBookmark::MemBookmarkDialogProc(HWND hDlg, UINT uMsg, WPARAM wPar
             // Auto-import bookmark file when opening dialog
             if (g_pCurrentGameData->GetGameID() != 0)
             {
-                std::string file = RA_DIR_BOOKMARKS + std::to_string(g_pCurrentGameData->GetGameID()) + "-Bookmarks.txt";
+                std::wstring file = RA_DIR_BOOKMARKS + std::to_wstring(g_pCurrentGameData->GetGameID()) + L"-Bookmarks.txt";
                 ImportFromFile(file);
             }
 
@@ -440,7 +440,7 @@ INT_PTR Dlg_MemBookmark::MemBookmarkDialogProc(HWND hDlg, UINT uMsg, WPARAM wPar
                 }
                 case IDC_RA_LOADBOOKMARK:
                 {
-                    std::string file = ImportDialog();
+                    std::wstring file = ImportDialog();
                     if (file.length() > 0)
                         ImportFromFile(file);
                     return TRUE;
@@ -699,7 +699,7 @@ void Dlg_MemBookmark::ExportJSON()
         return;
     }
 
-    std::string defaultDir = g_sHomeDir + RA_DIR_BOOKMARKS;
+    std::wstring defaultDir = g_sHomeDir + RA_DIR_BOOKMARKS;
 
     CComPtr<IFileSaveDialog> pDlg;
 
@@ -715,7 +715,7 @@ void Dlg_MemBookmark::ExportJSON()
             if (SUCCEEDED(hr = pDlg->SetFileName(ra::Widen(defaultFileName).c_str())))
             {
                 PIDLIST_ABSOLUTE pidl{ nullptr };
-                if (SUCCEEDED(hr = SHParseDisplayName(ra::Widen(defaultDir).c_str(), nullptr, &pidl, SFGAO_FOLDER, nullptr)))
+                if (SUCCEEDED(hr = SHParseDisplayName(defaultDir.c_str(), nullptr, &pidl, SFGAO_FOLDER, nullptr)))
                 {
                     CComPtr<IShellItem> pItem;
                     SHCreateShellItem(nullptr, nullptr, pidl, &pItem);
@@ -753,7 +753,7 @@ void Dlg_MemBookmark::ExportJSON()
                                     }
                                     doc.AddMember("Bookmarks", bookmarks, allocator);
 
-                                    _WriteBufferToFile(ra::Narrow(pStr), doc);
+                                    _WriteBufferToFile(pStr, doc);
                                     CoTaskMemFree(static_cast<LPVOID>(pStr));
                                     pStr = nullptr;
                                 }
@@ -770,10 +770,10 @@ void Dlg_MemBookmark::ExportJSON()
     }
 }
 
-void Dlg_MemBookmark::ImportFromFile(std::string sFilename)
+void Dlg_MemBookmark::ImportFromFile(std::wstring sFilename)
 {
     FILE* pFile = nullptr;
-    errno_t nErr = fopen_s(&pFile, sFilename.c_str(), "r");
+    errno_t nErr = _wfopen_s(&pFile, sFilename.c_str(), L"r");
     if (pFile != nullptr)
     {
         Document doc;
@@ -819,9 +819,9 @@ void Dlg_MemBookmark::ImportFromFile(std::string sFilename)
     }
 }
 
-std::string Dlg_MemBookmark::ImportDialog()
+std::wstring Dlg_MemBookmark::ImportDialog()
 {
-    std::string str;
+    std::wstring str;
 
     if (g_pCurrentGameData->GetGameID() == 0)
     {
@@ -844,7 +844,7 @@ std::string Dlg_MemBookmark::ImportDialog()
                     LPWSTR pStr = nullptr;
                     if (SUCCEEDED(hr = pItem->GetDisplayName(SIGDN_FILESYSPATH, &pStr)))
                     {
-                        str = ra::Narrow(pStr);
+                        str = pStr;
                         CoTaskMemFree(static_cast<LPVOID>(pStr));
                         pStr = nullptr;
                     }
@@ -865,7 +865,7 @@ void Dlg_MemBookmark::OnLoad_NewRom()
     {
         ClearAllBookmarks();
 
-        std::string file = RA_DIR_BOOKMARKS + std::to_string(g_pCurrentGameData->GetGameID()) + "-Bookmarks.txt";
+        std::wstring file = RA_DIR_BOOKMARKS + std::to_wstring(g_pCurrentGameData->GetGameID()) + L"-Bookmarks.txt";
         ImportFromFile(file);
     }
 }
diff --git a/src/RA_Dlg_MemBookmark.h b/src/RA_Dlg_MemBookmark.h
index 97d23c6f4..5f750c049 100644
--- a/src/RA_Dlg_MemBookmark.h
+++ b/src/RA_Dlg_MemBookmark.h
@@ -70,9 +70,9 @@ class Dlg_MemBookmark
     unsigned int GetMemory(unsigned int nAddr, int type);
 
     void ExportJSON();
-    void ImportFromFile(std::string filename);
+    void ImportFromFile(std::wstring filename);
     void GenerateResizes(HWND hDlg);
-    std::string ImportDialog();
+    std::wstring ImportDialog();
 
     void AddBookmarkMap(MemBookmark* bookmark)
     {
diff --git a/src/RA_Dlg_Memory.cpp b/src/RA_Dlg_Memory.cpp
index 52a17458f..7db57d0e7 100644
--- a/src/RA_Dlg_Memory.cpp
+++ b/src/RA_Dlg_Memory.cpp
@@ -1443,7 +1443,7 @@ void Dlg_Memory::RepopulateMemNotesFromFile()
     ra::GameID nGameID = g_pCurrentGameData->GetGameID();
     if (nGameID != 0)
     {
-        std::string sNotesFilename = g_sHomeDir + RA_DIR_DATA + std::to_string(nGameID) + "-Notes2.txt";
+        std::wstring sNotesFilename = g_sHomeDir + RA_DIR_DATA + std::to_wstring(nGameID) + L"-Notes2.txt";
         nSize = m_CodeNotes.Load(sNotesFilename);
     }
 
diff --git a/src/services/ImageRepository.cpp b/src/services/ImageRepository.cpp
index 709c33178..1d4a0034a 100644
--- a/src/services/ImageRepository.cpp
+++ b/src/services/ImageRepository.cpp
@@ -123,20 +123,20 @@ ImageRepository::~ImageRepository()
     g_bImageRepositoryValid = false;
 }
 
-std::string ImageRepository::GetFilename(ImageType nType, const std::string& sName)
+std::wstring ImageRepository::GetFilename(ImageType nType, const std::string& sName)
 {
-    std::string sFilename = g_sHomeDir;
+    std::wstring sFilename = g_sHomeDir;
 
     switch (nType)
     {
         case ImageType::Badge:
-            sFilename += RA_DIR_BADGE + sName + ".png";
+            sFilename += RA_DIR_BADGE + ra::Widen(sName) + L".png";
             break;
         case ImageType::UserPic:
-            sFilename += RA_DIR_USERPIC + sName + ".png";
+            sFilename += RA_DIR_USERPIC + ra::Widen(sName) + L".png";
             break;
         case ImageType::Local:
-            sFilename += sName;
+            sFilename += ra::Widen(sName);
             break;
         default:
             ASSERT(!"Unsupported image type");
@@ -151,7 +151,7 @@ void ImageRepository::FetchImage(ImageType nType, const std::string& sName)
     if (sName.empty())
         return;
 
-    std::string sFilename = GetFilename(nType, sName);
+    std::wstring sFilename = GetFilename(nType, sName);
     if (_FileExists(sFilename))
         return;
 
@@ -320,7 +320,7 @@ static HRESULT CreateDIBFromBitmapSource(_In_ IWICBitmapSource *pToRenderBitmapS
     return hr;
 }
 
-HBITMAP ImageRepository::LoadLocalPNG(const std::string& sFilename, size_t nWidth, size_t nHeight)
+HBITMAP ImageRepository::LoadLocalPNG(const std::wstring& sFilename, size_t nWidth, size_t nHeight)
 {
     if (g_pIWICFactory == nullptr)
         return nullptr;
@@ -405,7 +405,7 @@ HBITMAP ImageRepository::GetImage(ImageType nType, const std::string& sName, boo
     if (sName.empty())
         return nullptr;
 
-    std::string sFilename = GetFilename(nType, sName);
+    std::wstring sFilename = GetFilename(nType, sName);
     if (!_FileExists(sFilename))
     {
         FetchImage(nType, sName);
diff --git a/src/services/ImageRepository.h b/src/services/ImageRepository.h
index 693aa6464..e9e2e59ff 100644
--- a/src/services/ImageRepository.h
+++ b/src/services/ImageRepository.h
@@ -92,8 +92,8 @@ class ImageRepository
     void ReleaseReference(ImageType nType, const std::string& sName);
 
 private:
-    static std::string GetFilename(ImageType nType, const std::string& sName);
-    static HBITMAP LoadLocalPNG(const std::string& sFilename, size_t nWidth, size_t nHeight);
+    static std::wstring GetFilename(ImageType nType, const std::string& sName);
+    static HBITMAP LoadLocalPNG(const std::wstring& sFilename, size_t nWidth, size_t nHeight);
 
     friend class ImageReference;
     HBITMAP DefaultImage(ImageType nType);
diff --git a/tests/RA_Defs_Tests.cpp b/tests/RA_Defs_Tests.cpp
index 46ac1fd16..b383a4a3b 100644
--- a/tests/RA_Defs_Tests.cpp
+++ b/tests/RA_Defs_Tests.cpp
@@ -39,6 +39,9 @@ TEST_CLASS(RA_Defs_Tests)
         Assert::AreEqual(std::wstring(L"\xD83C\xDF0F"), Widen(L"\xD83C\xDF0F"));
         Assert::AreEqual(std::wstring(L"\xD83C\xDF0F"), Widen(std::string("\xF0\x9F\x8C\x8F")));
         Assert::AreEqual(std::wstring(L"\xD83C\xDF0F"), Widen(std::wstring(L"\xD83C\xDF0F")));
+
+        // invalid UTF-8 replaced with placeholder U+FFFD
+        Assert::AreEqual(std::wstring(L"T\xFFFDst"), Widen("T\xA9st")); // should be \xC3\xA9
     }
 };