I have a friend with a 2009 MBP running 10.7 that has been migrated from 2 other previous, older machines. I found that the minus button is greyed out for all accounts except iCloud. Additionally, whenever I try to add a Gmail account (haven't tried others), whenever I put in all the information and click OK, it will verify it and say the information was accepted, but then it stays on the dialog as though you hadn't clicked OK. If you cancel, the account isn't set up. Obviously there is some kind of OS corruption or permissions issues, but I'm wondering if I should bother trying to fix it, or if I should just wipe it and re-install.