I just upgraded to 4.10. I've been working for many days building a video.. I did frequent "Save Project File As .." along the way (always to the same filename). Today, I made some edits I didn't like, so decided to open the saved project file to undo them, and got "The provided file might be damaged. Do you want to load it anyway?". I noticed there are a number of files in the folder where I save the project named "project-name_backup(n)". I don't know what created those files, but judging by the creation date/time of them, they were likely made when I did the "Save Project File As", or were automatic backups done by VP. I've tried opening several of those too, with the same results.
I answer "yes" to the error msg to go ahead and load the save file. It fills in the media bins with the clips, and lists the 4 sequences I had, but the sequences are empty.
At this point, I'm livid because it looks like I've lost many days of work. Any ideas?