Preview Crashing

I am having this issue - when I "play the timeline" in the working environment, not preview or after you publish - I have saved as a new name - I have imported this project over several dozen times already into a new project. I have uninstalled the apps, used your clean utility and reinstalled. I now save EACH time I do anything. This is insanity - I already have a case due to all the other problems and crashes - this is a new one to add to the lot. I have each scenario in its own file for now just to get through development and review. Plus when I change from expanded font, which seems to be part of the other issue - it removes all my animation timing by paragraph and formatting. I am not sure what is happening with your software but the "gremlins" I have experienced over the many years have grown to full blown adult trolls and wreaking havoc for me and my students.