Audacity freezes - can't save, do anything

First time posting, but it’s kind of dire straits. I’ve used Audacity (2.2.1) on and off over the last year for a few small projects. Now I’m using it for a larger one, and I have to edit together three different files into one coherent project. My file, which I’ve already worked on a little on Audacity, is fine. Today I received via email the other two I work with. One opens fine, the other doesn’t (but I think that may be an error on the other person’s part).

My problem is that in the process of trying to edit things together (copy+pasting parts of audio into different project files), sometimes audacity will freeze up and not let me do anything. I can click on the track and change where “play” will start from, but the buttons are all greyed out and won’t do anything. Saving is impossible - I’ve noticed sometimes that when I go to ‘File’, ‘Save project’ will be greyed out and unclickable, and I can only ‘Save Project As’ (which is irritating, but especially because it always seems to result in the larger problem stated above).

I really don’t know what to do. I know there’s advice saying not to have too many programs running in the background and make sure you have space on your drive, but I don’t have too many and I’m sure I have space. Audacity seems like it’s literally breaking - I tried to reopen a file and it gave me a crash report, and when I tried to look at the details of the report, my ENTIRE computer froze so badly I had to shut it down and restart. This project is due SOON and I don’t know if it’s my computer, Audacity, or my project teammates’ files being super weird. Help?