Anyway. It's biting me. After the upgrade I had a quick look at the tutorial project - then I used the 'Find of type- Scrivener project' command under File. I selected an old project - it said I needed to upgrade. A few whirrs later Scriv says
'The document ... could not be opened.' No further message.
I tried a couple of other projects, and the same thing happened. I tried a couple of projects I don't care about and bingo, it opened.
Unfortunately on the ones I do care about I can't edit them at all. They're old - 7-8 years old. There's no permissions issue I can see (I set Everyone to have Read-Write access on it and same thing persisted.
A variation of the message I'm seeing is the below. (Ellipsis replace stupid folder names)
'No .scrivx file could be found inside "/Users/.../Documents/Writing/.../MQ-final.scriv". It may be missing or corrupt, possibly because of a problem with the device on which it is stored, or because of a synchronisation problem.
Try ctrl-clicking on the project in the Finder and selecting "Show Package Contents", then look for a file with the file extension'.scrivx'. Ensure it has not been renamed by a backup routine. If it does not exist, try restoring from a backup.
I have done this, and there is no .scrivx document (although all the RTF files are there to keep me sane). This looks to have been an upgrade problem - is there a way to fix this?