Placeholder for pre-release previewer variable status

[GitHubRulesOK]

Not opening as multiple self induced issues just a place to show different OS behaviors based on one version currently 3.4.14557

Using fairly fresh Win 10x64 as baseline, correctly install via "run as administrator" and option "for all users".
PDF previews no problem (blanks are known limitations e.g. password)
CBX previews generally not a problem (none tested are password protected)
Xps/Oxps preview by MS (fit width with zoom option)
Images thumbnails and preview by MS (untested yet for HEIC TGA WEBP)
CHM no previews but TXT HTML etc by MS
ePub icons but no thumbnails nor Preview showing in 3.4.14557
DjVu seems problematic unknown if its the one file tested but has caused glitches in other units
FB2X untested for Z or not

Win 11 outside Sandbox ( I am sole basic admin user) currently install NOT for all users but do only select previewing (needs elevation) and see
PDF previews no problem
CBX previews generally not a problem can even include Heic
ePub icons but not thumbnails or Preview not showing but thought? had done so before

Others seem to be as above so no need to select all users , elevation works ??

Win 11 inside Sandbox (I am sole elevated admin user, no need to authorize, check previewer and here additionally search filter, but again do not bother choosing all users)
PDF previews no problem, HOWEVER no thumbnail previews, only red Edge icon (SumatraPDF not always the default)
CBX previews are variable problem (heic never shows in previewer) thumbnails show as icons
ePub icons (not thumbnails) and Preview not showing in 3.4.14557 but thought? it had done so before
Some of those behaviors may be down to no image thumbnails available

Win7 x32 (similar to 11 sole basic admin user needs elevate to add previewing, so should be OK)
PDF previews no problem
DjVu shows bad preview and seems to crash something is that related to odd file or a different legacy previewer, Cuminas?
CBX previews and thumbnails generally working
ePub icons (not thumbnails) and Preview not showing in 3.4.14557 but thought? it had done so before

Summary so far
there is a potential problem with DjVu and thumbnails especially inside Sandbox (not associated with SumatraPDF or image support?)