I am having exactly the same problem. I updated my OS to Sierra (huge mistake i've now realised) and updated all my Adobe apps. Now when i create a new document, save it, then come back to it i get the damaged file (error code 4) and the work is lost. Yesterday it happened twice when i tried to save the open file. Have just checked all my files for today and everyone is now damaged and lost. Unbelievable
I am having exactly the same problem. I updated my OS to Sierra (huge mistake i've now realised) and updated all my Adobe apps. Now when i create a new document, save it, then come back to it i get the damaged file (error code 4) and the work is lost. Yesterday it happened twice when i tried to save the open file. Have just checked all my files for today and everyone is now damaged and lost. Unbelievable