Recently I created a catalog on a portable drive so that I could use it on both laptop and desktop. Up til now it has worked fine I could upload photos to the portable drive, edit them on the laptop and see the edits on the desktop or transfer them to my NAS and they would be available on either computer. Today however I keep getting the error message on my laptop that the catalog is corrupt, on the desktop it is fine. Any suggestions?
If you haven't been making regular backups of your catalog file (why not?), then immediately make backups.
If the catalog is corrupt on one computer, then somehow it is either corrupted or the hardware connection between laptop and external HD is not working properly.
You might want to try this. Unzip a recent backup and use that. If that doesn't work, unzip a recent backup and put it in a different folder than the original, and if that doesn't work, unzip a recent backup and put it on a different disk than the original.