Do you face this issue while creating new compositions also? Can you please clear your preferences(Delete the directory Library->Preferences->Adobe->Edge Animate) and try.
If the issue still persists, pl share some composition on which you get the error, with us.
As you suggest, I deleted the prefs file. Plus, I have un/reinstalled for a third time, too.
I created a new simple animation using symbols. A line of text should fly in. By clicking that text, a submenu should slide in.
Before going too far, I closed and reopened. I get the same "composition failed to load" error. Compositions would not load into Chrome for preview, either.
Files found here: Edge Troubleshoot
Many thanks for looking. I'm basically unable to use AE at present.
It is a pretty vicious error.
P.S. I use Edge Inspect, too.