@aabrams I was going to mention that whatever you do, do not close the program, but I guess you already did. In that case it’s possible that the internal files were lost, but we’d have to inspect the file to be sure.
While you’re using v0.6.4 are you using the 32bits version or the 64bits version?
Also what is your current macOS version?
Additionally can you please send us the file through wetransfer.com so we can review what was lost and see if we can recover something?
Here’s a GIF showing how to use Wetransfer to send an anonymous link, also the files will be deleted in a week so don’t worry about having to delete them later.