Playback controls not working

Hi All,
I have a problem with Musescore constantly dropping off the playback controls (i.e. they remain unable to use - or aren't live). I have followed the fixes including downloading sound fonts and installing and reverting to factory settings and I keep having to go through that process because the playback controls again drop out. IS there a permanent fix to this problem that anyone knows about. It seems to be common as I have students who have the same issue. I've attached the file that was most recently used.
with thanks.
Nick