Unable to read .tvg files in toon boom storyboard 20

I was gone for quite a bit from storyboarding. I decided to go back to one of my projects and it just says that it can’t read tvg files (like all of them) and I can’t see my drawings once I click on them, they all disappear. There isn’t a solution I can find, I tried deleting the main files and replacing them with the backups, but that didn’t work either. There’s also a problem with one of my projects when opened that says, “Your project has a locked file”, and says that it’ll corrupt the file while it’s still open.

I’m not sure what I did, it’s been months since I last touched this program. Help me, please.