Macworld reader Carah received an error messages from Photos in macOS I’d never seen before—but which is fortunately easily diagnosed and solved.
Carah was trying to free up space on her internal disk drive, as it was nearly full, so followed instructions in another Mac 911 column on copying Photos libraries to an external drive.
After completing the copying and launching Photos with the Option key held down to select her new external library, Photos gave her an error on selection: “The library ‘library name’ is stored on a drive that uses an unsupported disk format. To access this library, copy it to the internal drive on your Mac or to a drive that uses a supported format.”
