THE FILE DOESN'T OPEN

Hello, my name is Daniel and I'm from Portugal, I've been using Musescore for
almost 2 and half years, it is a good software, and it is easy to work whit
it.
I didn't have any problem until now, I started a new project and I was
writting a song, I didn't finished it so I saved. In the next day, when I
tried to open the file it didn't open, can you give me some help, I would be so
grateful.

Thank you for all, and happy holidays.