Sound settings not saveable on mate desktop

The sound on a Raspberry Pi 4 is not really saveable. At first I don’t understand why there is only the setting mute or not possible - the rangeslider is without any action.
Then (and that is the major-issue) the settings were not saved. I “activated” the sound but on a restart it is still deactive again. Maybe this has to do with the other issue ( Automatic icons on desktop after reboot ), but now the time is running and this has to be set onto 100% on every start. So what can I do?

As workaround I would create a file and put it in the autostart with the command:
amixer controls | grep layback | grep -v ' Ma' | xargs -I '{}' amixer -q cset '{}' 700%

not the best way, but helpful for the moment.

Sounds like of there is a permissions issue. You login as non-root user? Does it work when you add that user to the audio group, like

sudo usermod -aG audio username

On the other hand, it really looks like it’s related to the not saved desktop icons.

Are other changes on the filesystem (creating/changing/deleting files) from within the desktop session work, else does it work when doing so from the console outside the desktop session, e.g. via SSH?

To be in the audiogroup doesn’t change anything. For me it looks like a relation to the other topic, but not sure.

Yes, I’m using the desktop for the non-root user. Even if I change it via root the sound is deactivated after reboot for root and the non-root user.

Okay, let me try to replicate.