iCloud System Preferences- Find my Mac won't check

[KoolAid-Drink]

This is frustrating. Out of the blue, in System Preferences > iCloud, the 'Find my Mac' setting won't checkmark. I check it, it asks if I want to allow my Mac to be discovered, but then the checkmark just disappears.

I may have accidentally deleted a PLIST relating to Find my Mac, because my iCloud settings kept prompting me to enter my password, even though I had entered it correctly, and even signing out of iCloud in System Preferences and re-signing in would not work properly (it would just spin forever when entering my password), so I deleted all PLISTs relating to iCloud and signed out in Safe Mode, then re-signed back in, which worked, but now Find my Mac won't work.

Ideas or solutions?

 

[KoolAid-Drink]

Update:

I solved this by doing an in-place install of Yosemite, only after testing in a new user account. Word of advice: be careful deleting .plist files in Mac OS X. Lesson gleaned: backup the .plist files if you have to delete them.