The new Crushing Update

Thankfully, i love that my last distrib. of 3.5 version of Musescore is saved on an old macbook.
Anyway, a month ago i started working with a new Musescore, and th process is terrible...
Now i have a score, that was not saved after finishing it, and i spent more 4 hours to re-write it.
And then, another problem comes - program CRASHES every time i try to open the score parts. The thing is that i can open all of the parts, instead of one, that crashes the programme...
Maybe there are some fixers that can help me? I like Musescore very much, but i don't like that i spend much more time fighting with crashes of a fresh-updated programme...