Could not complete your request because Photoshop does not recognize this type of file.

[Odetaa]

Hi, please somebody help me to understand, why the newst photoshop 2021 version do not recognize mp4 files? My computer is MacBook pro 13, M1 silicon. Befor 2 months I could open mp4 files at the same computer, at this momemnt it does not recognize this format. 

[War Unicorn]

Have you tried an uninstall/reinstall yet? It sounds like either the plug-in needed to work with MP4s might have been corrupted or is missing.

[Odetaa]

Hi, Yes I have tried to reinstall, it has not helped :(.  How I can fix the problem with plug-in if it is this case?

[War Unicorn]

You could try the CC Cleaner Tool, but it's *very* involved, *especially* if you're using multiple Adobe apps. (Follow everything to the letter.)

https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html

[Odetaa]

Hi, 

Thank you for your help, but after all cleaning it is the same problem. I have installed software again after cleaning and it is not work. 

[War Unicorn]

Out of curiosity, can you play any MP4 outside of Photoshop (e.g., QuickTime)?

[Jeremy@M]

I wonder if this is an Apple Silicon instruction set issue. If the OP didn't have an issue previously, maybe @Odetaa  was using the Intel version of PS via Rosetta 2? I'm on M1 Max and having the issue as well. There's also not an option for Layer > Video Layers. I can only work with frame animations.