All sounds are gone (saved and factory)

Function Mute enters the ‘Sounds’ of my Rytm.
Unfortunately, when I go there: it says ‘No + Drive Matches’.
Not for BD, BT, MT, HT, enz…
Also the Pool is empty.

Where can it be? Can I reload the factory content?

in sound browser, is there any tag selected for the filter?
if you create a sound and from sound manager try copy it to either pool or +drive, are there any numbers next to each item in the list that shows up when selecting ‘copy to…’?