I just used Applecare for the first time and want to express my appreciation for first class service. The problem seemed simple enough - I couldn't log into iCloud from one account (only) on my iMac. It turned out that permissions and ACLs were seriously messed up somehow. Repairing permissions had not helped. My iMac has an SSD and a 1 Terrabyte hard drive. I had set it up to move the users directory to the hard drive - which is not a recommended procedure by Apple - but it has worked fine for over 5 months. The technician didn't complain about a "non-standard" configuration and took the necessary steps to restore my system to working order. Even though I suggested early on in the process that I could set up a new user account to eliminate the problem, he insisted on fixing the root of the problem. Hats off to Apple Support!!