Ask

Backups stop in Sierra

Since I upgraded my Mac to Sierra, Time Machine has stopped backing up to my Synology DS411J NAS drive, although I can still log on to the drive directly. I’ve tried deleting my old backups, and unmounting and remounting the drive, but when Time Machine does make a backup following such maneuvers, it hangs when preparing the next one. How can I get Time Machine working again?

This problem hasn’t just affected many users of Synology NAS drives, but people using alternatives from some other vendors, too. There have been long discussions and suggestions of solutions on Synology’s and other support forums – see bit.ly/2fbYBCR for just one example – but no one has yet discovered a lasting answer.

It’s probably the result of a mismatch between Synology’s software and macOS Sierra. To convince Time Machine that it’s asuitable backup store, the software running on the NAS has to follow various protocols. Sierra has apparently changed its side of that, either intentionally or due to bugs, and thrown the process off.

It’s always worth checking that your NAS is running the latest version of its software, and that you’ve followed the instructions in its documentation fully. Sometimes software updates can silently alter your Mac’s network settings, for example.

Your best option is to raise a support ticket with Synology. The company should be