unable to select sound source

I used a VST (addictive keys) for playback of my sheet music and it worked fine. The library of this VST is on an external SSD. Now when I reopen the score (with SSD connected) musescore freezes and I have to force quit.

Musescore now has no sound selected in de mixer and I am unable to select the default or an VST...

This seems quite a bug to me and I am unable to play this score.
When I create new score: this has worked and the playback reverted to the default. But the second time, the software quits when trying to load audio samples.

I have reverted to factory settings but did not perform a reinstall.