This worked great for me. Thanks!
My Compressor problem started when I noticed Compressor was stalled and “Startup Disk Full” appeared on my usually spacious hard drive. I discovered that compressor creates temporary files in the var/spool/qmaster filepath, and fills up your hard drive (my qmaster folder was 25GB). So I deleted everything in the qmaster folder. Dumb! Compressor was confused. But after your steps above, everything works great again. Thanks!