Windows 10: Overlay Icons from Shell extension not working correctly

I have a Shell Extension which changes the overlay icons for folders and files in my app folder. On Windows 10 it works as expected but on Windows 11 they are not shown/set. I don't know if this is a known issue, but I hope someone can help :

:)

 

Shell Overlay Icons not showing in explorer

I ran into an very odd variant of an issue. I had a Windows program using shell overlay icons that were not appearing in windows explorer. What makes this odd is that they WERE showing in some "Save" and "Save As" dialog boxes (MS Office and Firefox), but weren't in others (Chrome). I had checked all the normal things, such as making sure the icons appeared first in the

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers

registry key. I looked at the WOW version as well. I even checked the DPI settings as suggested in this question: TortoiseSVN shell overlays only showing for medium and large icons in explorer

None of those worked, but I finally figured it out so I thought it would be nice to put up in case someone else is tearing their hair out over this. The system I ran into this on is Windows 10 and I haven't tested against older versions of Windows.

 

Windows 11 Shell Icon Overlays

Hello,

I am using a shell extension in Windows 10 that is setting an icon overlay on specified files. When the file has an Offline Attribute (System.IO.FileAttributes, System.Runtime.dll), I am relying on the default grey cross icon from Windows for these offline files:



Unfortunately in Windows 11 the icon has been changed to a brown box:



This makes me think that the Offline attribute that I am setting on the file is resulting to a different icon in Windows 11, perhaps the old icon has been either removed or changed with this brown box icon. Can this be confirmed and is there a way to access the grey cross icon?

 

Shell Overlay Icons not showing in explorer

If you happen to see such symptoms (shell overlays not showing up in some application), you use 64bit Windows and the answer above didn't help you, make sure that your app properly registers both shell extensions (one for 32bit and the second one for 64bit). If only 64bit dll is loaded, you won't see overlays in 32bit apps.

32bit shell overlays are registered in: