Software closes when trying to open file

Hi everybody,

I was trying to edit a file (a song with solo, choral parts and piano): I was copying parts from the piano score to the choral score, saving the file, then telling musescore (I'm using 3.6, the portable version) to not show the piano score anymore (I wanted to print out a score for the singers only). Then the software crashed. I can re-open it and open another file, but the file I was working with is now crashing the software every time I try to open it! This one is important for me. Any idea, what happened/ how I can still open my file/ how I can prevent something like this? I uploaded the file, maybe someone can try it out...?

I'm thankful for any help! And sorry for my english...

thanks, ChillySue