I was messing about with the snowstorm tutorial and wrecked my project. No worries, I have a Time Machine backup. I recovered the backup and then tried to open it. Elements couldn’t open the file. Weird. Looking at it more closely, I had selected “keep both copies” when restoring. The file name generated from that had “(from backup)” appended to the file name but after the elements suffix. I changed the name to allow “.elements” to be at the end of the name and all was well. I’m not sure if this is something I did or if the suffix needs registered somehow. It was quirky but it did work.