Photoshop files locked

We have been rolling along fine, but now suddenly photoshop files often will not save. Get a message that files are locked. I cannot detect a pattern. Sometimes we can do a save-as and succeed, sometimes not. Sometimes save to a new folder, sometimes not. Also have tried different file formats. Again, no pattern. It does not do it to every student every time, but most of them most of the time. Happens both with existing files that students open, and new files they create themselves. And even when it indicates it is saving, file may actually be only 8k and will not open because it is "truncated." 

I've tried wiping out preference files for photoshop. It will seem to be fixed, but then crop right back up. Since it is so inconsistent, I never know if anything I do actually has an impact or it it is just a coincidence.

Now, I should point out that the problem cropped up after I did the 10.4.3 update. But it did not happen right away.

And here is one more piece to the puzzle. I just added a new student today. She was able to open and save fine. 

It only is photoshop. All other file types are OK.

Any ideas?

Wayne Welch    

Teacher / Adviser

Computer Graphics / Video / Yearbook

Tulare Union High School

Tulare, CA 93274

559-686-4761 x2608

email@hidden