The OS X 10.11.3 update brings backup woes
QI recently upgraded my 15-inch Retina MacBook Pro (late 2013) to OS X 10.11.3, which has caused serious problems with iCloud and Time Machine. The latter has been unable to make any backups since that update in January. Looking in the logs, backups start correctly, but still seem to be running an hour or two later, forcing me to restart the Mac. Why are they not completing properly?
AHaving checked through your logs, these backups appear to be running normally, and do not encounter or report any errors. They are also intended to be very large: over 20GB, which could easily take several hours, particularly if run over Wi-Fi to an already well-used set of old backups.
It is probable that your update did not ‘take’ properly, leaving some parts of OS X, particularly Time Machine and iCloud, not fully functional. The best way to fix that is to download the 10.11.3 Combo updater from apple.co/1QGLsze and install it over the top of your existing system.
Once that’s complete, let your MacBook Pro run its next backup, which may require that you leave it running overnight to complete.
It that does not work, your backups may have become damaged, so it may be worth checking and repairing the drive using Disk Utility before attempting another backup. Errors in Console may then give better clues.
Low-level issues on a drive may get in the way of Time Machine making a successful backup to it.