You shouldn't have to. Two things to check:
1. Are you running MC from the Applications folder? Or are you running it from a DMG image? If you haven't copied it to Applications, you should do that.
2. Sometimes when you have an older version of MC installed (like MC20), it will "steal" the license, when you run the MJR (licensing file that you get via email). In these cases, you have to cut and paste your license key (the big string of letters and numbers) into the licensing dialog box in MC. Then it will take.
Brian.
