Every start of KDE the preference "Use VLC to open *.mp4 files" is reset to "use Gnome Videoplayer...).

How can I fix that?
This is with the latest application and Plasma versions within fully updated ARCH.

I explicitly used the KDE systemsettings for application preferences to set VLC to the highest priority for opening mp4 files.

thx, p.

Same as viewtopic.php?f=66&t=130749 ?

Thx for the hint.

I checked the arch wiki but the information is dubious and partly outdated, it seems...

How to use the $HOME/.config/$desktop-mimeapps.list as override?
Do I have to name it ~/.config/gnome-mimeapps.list?
What's the correct filename for KDE (I tried "kde-mimeapps.list" - doesn't work as override...)

What is the role of the gnome-defaults.list (depreciated it says in the wiki)...

So my question is: Where does KDE (in its latest version) save the file preferences and how to make sure no other settings (like the ones by the latest gnome-desktop) does override it - at least while in a KDE session.

I'd appreciate some details here,
thx a lot for your efforts, Rog131, but please give me some more in depth clarification here.

cheers, p.

Now I am even more confused as before:

To identify the files where the settings for mimetypes and application preferences are set,
I have done the following:

- I deleted (renamed) the file ~/.config/mimeapps.list
- I deleted (renamed) the folder ~/.local/share/mime
- checked the folder ~/.cache for any other preferences files but found none

Now I changed the preferred application for *.mp4 files from "Videos", apparently the Gnome default,
to "VLC Video Player", which is my preference...

Immediately after pressing "Apply" the order of preferred applications switched back to "Videos" on top.
I had to repeat this step - now it sticks - but I know for sure it'll change back after the next login (?), package update (?), session start (?)... which is the culprit I do not know...

Now I checked the locations of the alleged mime type preferences file (see top of this post) -
none of the files I deleted or renamed has been rewritten... they all seem obsolete!

So, please, where does KDE save it's file type preferences?
How do these preferences interact with the files mentioned above?
Where is some documentation on this (I tried the ARCH WIki but it's outdated and a mess...)?

Oh, after reading other posts, I've done a complete "sudo chown -R myuser:myuser /home/myuser" and checked the file permissions are all mine - so it's not that...

thx for your help,
piedro