My 2013 rMBP regularly freezes (screen stays on but freezes as well). I have Yosemite 10.10.1. I couldn't see such behavior in 10.9 and I don't think it's a hardware issue (had the machine serviced and an Apple Hardware Test was performed, no issues found).
In the console I found the "Previous shutdown cause: -112". Now, I found various lists and also a header file where this error code occurs but it probably is not connected to this issue.
Anybody has any clues regarding this problem? It happens at least once a week. Thankfully most data is preserved after the restart, but it is worrisome anyway.