[DigiTechSupt]

When we've had sessions sent to us that experienced this problem, it's been due to session corruption. Depending on when and how the corruption occurred, you may be able to either:

1. Use Import Session Data from a new session to import tracks one by one from the corrupted session. You'll almost certainly have at least one track that cannot be imported due to corruption.
2. If you can't use Import Session Data (you get the same error when selecting the corrupted session in the Import dialog), you'll have to see if you can open a previous version or a backup.

I strongly recommend a regimen of 'Save As..' when you're working to have the best chance of data integrity in the case of corruption. Merely doing a 'Save' every few minutes means you have only 1 session file at any time and, if that session becomes corrupted, you're relying on your session backups - which may also be corrupted, since they're based off the same session.

The better method is to do a 'Save As' every 10 or 15 minutes, this way you run a much lower risk of losing important data and time. My method is to put a version number after each session name - such as 'My Song_v1' - then increment the number for each save, using 'dot' versions as indicators of minor changes and whole numbers for major changes (My Song_v1.1, My Song_v1.2, etc.). This will give you a completely independent file for every save.

Always have 2 copies of any critical data or sessions and have a utility or script handy that will do an auto-backup of your data when you take a break. I use SuperDuper and have it open as I work - when I go to take a break, I hit the 'Copy Now' button, which does a sync of my working drive to a backup drive.

Hopefully one of your session backups will open and/or you can recover some of the data from this session.