My Canoscan 8400F started misbehaving after I upgraded to OS X 10.5.3. I use PhotoStudio to acquire scans and I get the message: "The necessary file could be missing or damaged, or some settings are incorrect. Reinstall the scanner driver. Scanner driver will be closed." I tried deleting and reinstalling all Canon files (from the Canon website); same for PhotoStudio. Canon recommended repairing permissions then rebooting. None of this has corrected the problem. I bought VueScan and the scanner works with VueScan. I can then open a saved scan with PhotoStudio and edit it but I would rather not have to take this extra step. Any ideas appreciated.