MP4 files associated with VLC are all white/blank now

[Eagle-Eye]

Hello,

I have the most current version of VLC Player (v3.0.20) installed on Windows 10 Pro. I previously associated VLC Player with all video files by setting VLC Player as the default app in the Windows system settings and if that did not work for all types of video files, I used the Windows Explorer context menu ("Open with", ...) to permanently associate VLC Player with the specific file extension.

Now, I have the following problem: Although the association with MP4 files is still there, meaning whenever I double-click on an MP4 file, it is opened and played by VLC Player, the icon for the MP4 files is just a blank white sheet instead of the regular VLC Player icon, the orange-white pylon. The strange thing is that the regular VLC Player icon is still shown for MP3 files, AVI files, MKV files, ect. Just the MP4 files have the blank white icon.

Under column in Windows Explorer, it also shows "MP4 Video File (VLC)", so the association is really recognized by Windows, it is just a problem with the app icon.

What I tried so far:
- deleting and rebuilding the icon cache -> did not help
- associating MP4 files with a different video player (via Windows Explorer) and then associating them again with VLC Player -> did not help (Side note: The file type icon was changed to the other player's icon when I did this but reverted back to the blank white icon when changing the association back to VLC Player.)
- setting a different video player for video files in the Windows system settings and then making VLC Player the default app for video again -> did not help
- deleting the complete entry for .mp4 under \HKEY_CLASSES_ROOT\ in the Windows registry -> did not help (changed the white sheet icon to a white sheet icon with a golden coin on it) (Side note: Restored the original entry after the "experiment".)

What could be the problem and how can I fix this (e.g. by changing something manually in the Windows registry)?

[Lotesdelere]

Displaying thumbnails is Windows Explorer's job, not VLC's job.