Hi Eydie,
I'm sorry to hear you ran into some freezing as well! Does it only happen when you're working on this one project, or anytime you're working in Storyline? You mentioned removing previous versions, do you mean earlier copies of the .story file?
Can you also check that you're using the latest update, Storyline 360, build 3.21.17083.0? You can check by going to the "Help" Tab -> "About Articulate Storyline".
Lastly, I'd want to make sure you're also working on a local copy of your project and adhering to the other guidelines here to prevent odd behavior.