I am a high school art teacher and this happened to one of my students. He was working on a PSD file, vectoring an image when PS6 quit unexpectedy. Now when we try to open the file there is an error message "Could not complete your request because it is not a valid Photoshop document." It still has the .psd extension. We are using Mac OS10.8.2. I tried opening it in Illustrator, Preview and Graphic Coverter without success.
Any thoughts on how to get it to open would be appreciated.
Photoshop 6 is very old are you sure your not using CS6. When CS6 crashes if you have autosave on and you have made changes and an autosave time has expired a recovery PSB file should have been saved by Photoshop. Photoshop CS6 should open that recovery PSB file when that userid opens Photoshop. If he open a PSD file to begin with and can not open it now then something must have corrupted that PSD file after Photoshop opened that file the first time. Did he try saving over the original PSD before CS6 crashed for something must have written to the file and corrupted it.
I'm sorry to bear the bad news that corrupted PSD files can almost never be recovered.
Does the student have any backup copies?
Most folks who use Photoshop for a while begin to realize that saving into multiple different master files is a good practice. I suppose Time Machine could be helpful in this case as well.
Is it Photoshop CS6? I ask because that version is supposed to recover a document lost to a crash on the next run of Photoshop. It automatically saves backup copies from time to time.