For no known reason, I started seeing an error about only apple apps can access something.. I don't know what it was anymore because of reasons you'll see in a second. icloud/imessage decided to log off, and I get the "keychain login cannot be found" error that you can find all over the !@#!@#1 internet dating back years with no fix ever said. I restarted and reset PRAM which was a possible solution to things, but when I got back on, I've found that icloud/imessage STILL won't log in, various preference files seem to be gone for different programs, Tabs Mix preferences in firefox, and the firefox history is gone (which is why I can't recall the error above).. I was just finishing re-setting up this mac with a fresh install after a problem last week. I'm waiting on a new drive, so there's no backup to revert to right now.. I hope someone has an answer or solution to this.