When you save and open files across a network or from removable media, many variables affect application performance. Therefore, some problems occur more frequently when you work across a network or from removable media than from a local hard disk. (Network-related problems include damaged files, denied access, or slow performance.) In these situations, Photoshop can return one of the following error messages:
- "Could not complete this operation because this file is in an unknown format."
- "Could not complete the request because the file is locked."
- "Could not save because of a disk error."
Note: Problems using Photoshop files across a network or from removable media can be intermittent or delayed.
Adobe Technical Support only supports using Photoshop and Adobe Bridge on a local hard disk. It's difficult to re-create or accurately identify network- and peripheral-configuration problems.
Important: External hard drives should work with Photoshop without a problem, although depending on how they are connected, might be slower than working with files on your internal drive. Testing against these drives by temporarily disabling them and working exclusively on an internal drive is appropriate. However, Adobe is not stating that there should be regular problems storing files and working with external hard disks.