Hi RetroDon,
Commiserations!
Unlikely, but is it possible you have two different versions of iMovie installed ... you could check in the "Applications" folder.
(Also, some of us may create a presentation in Keynote. instead of iMovie).
Have you tried viewing the "package contents" of the iMovie "Library" folder ....
(ie: projects may be there, just not not loading to iMovie?)
_________________________________________________________________________________
Wondering which Mac Model,
which Mac OS version,
and which iMovie version you are using
Here are a couple of discussion threads on similar missing iMovie projects, with (maybe) some helpful tips
All my iMovie Projects have disappeared - Apple Community (Sierra 10.13.4 + iMovie 10.1.8)
https://origin-discussions-us.apple.com/thread/253524323. (Mojave 10.14 + iMovie 10.1.12)
_________________________________________________________________________________
Resources:
Online iMovie User Guide for Mac:
iMovie User Guide for Mac – Apple Support
You might want to reach out to the iMovie support team:
(There's a "Get Support" link at the bottom of their website (link below.)
iMovie - Official Apple Support
All the best :-)