PSE 20 on Mac wouldn't allow saving files and said I didn't have permissions. Looking through this site, I found a fix by resetting preferences to default, which works. Unfortunately this only works for a short time, time to edit and safe 5 to 10 photos, then starts again. Since resetting preferences requires restarting the software, this is more than a minor inconvenience! Does anyone know a permanent solution to what appears to be an Adobe bug?