tl;dr A recent installation of VLC VideoLAN on freshly installed Windows 11 revealed that many popular video file extensions are not registered with this player (many, many others are). I am unable to register them manually because I can't find them on the list of available extension in Default Apps. What should I do? How to manually register some file extension with some (default) applications in this case?
The problem with video file types
I have a problem in freshly installed Windows 11 that certain well-known apps (VLC, IrfanView) does not register all of their file extensions correctly. I don't know why.
For example, I have just installed VLC and it registered many extension that it supports, but not .mp4:
When I try to fix this by going to Tools → Preferences → Operating System Integration and clicking Setup file associations..., I see a message saying: "To change your default apps, go to Settings → Apps → Default apps". So this is pretty much a vicious circle.
I have tried to manually bind .mp4 extension with VLC program, but to my extreme surprise I cannot find it in my system:
The same goes for virtually every video file extension that I use daily (namely: .avi, .wmv, .mkv). A lot of "weird" extensions are registered, but not these ones:
Some more observations
The file's icons all the time seems to be the one from Windows Media Player:
It remains unchanged from the very installation of Windows 11 even though WMP was removed few days ago.
When file is stored in OneDrive then double-click behaviour is as follows:
- When clicked for the first time -- downloading the file to local disk
- When clicked for the second and following times -- an icon / file status changes from Keep on this device to Always keep on this device and back; no program is ever launched
When file is stored in non-OneDrive location then double click depends on when the file execution attempt was made. When in Total Commander, following error message is shown:
When file is double-clicked in Windows Explorer then Pick application dialog is displayed:
Unfortunately, in Windows 11 the Always use this app... checkbox is no longer available in above mentioned window and picking application process must be repeated with every file execution.
The same problem with image file types
I recall that I had an exactly the same problem with IrfanView registering all of its image extensions, but not the popular ones: .bm, .jpg, .png and .gif. I also couldn't list them on the list in Default Apps.
But, after a day or two, some magic has happened and these extensions started to appear on the list. And I could register them with IrfanView manually. This time I wasn't so lucky and nothing has changed for past 2-3 days.
The question
This is a quite long post that narrows down to a simple question:
What to do in this case?
Is there any way in Microsoft 11 to add a file extension registration, if that extension doesn't appear in Default Apps window? Is there any system-wide way or must I use some third party software?