Unable to rename mp4 files

If the file is opened I am unable to rename the file. This only happens with mp4 and not any other format. If the file is not used by any application I can rename just fine in explorer

That is normal and it happens with other formats as well.

no don't think so. I am unable to rename ONLY the mp4. Other formats can be renamed while file is opened.
Any way to troubleshot this maybe to see what's going on. I am running the video player program as an ADMIN, but still no luck.

thank you.

Running the player as admin has no benefits at all. You should not do that.

Again, it is not normal to always expect to be able to rename a file when it is in use. It depends on the situation.

Here is how you can make it work:
Codec Tweak Tool > Preferred splitters > Select "use merit"

After this, you should see "File Source (Async)" + "LAV Splitter" when looking at: MPC-HC menu > Play > Filters. Before you would see "LAV Splitter Source". That is same splitter, but with integrated source filter, which is what reads the file. "File Source (Async)" opens the file in a way that allows renaming.

If you don't see "LAV Splitter" but some other third party file that you have installed, then you can solve that by adding LAV Splitter as a preferred external filter in the MPC-HC settings.

Now you may ask why doesn't it work with LAV Splitter Source. Well, my answer is: go ask its developer if that can be changed. But again, I say that it is not a given to expect to be able to rename a file that is in use.

is the same setting change for xnview classic?

tried it and 'yes' it does work for xnview. thank you very much, sir!