I manage 2 networks -- both are having seemingly identical problems. Everything worked well until shortly after Sierra upgrade.

The problem I am trying to solve is that Time Machine is no longer backing up in either place. I get errors that "Backup Disk Not Available". I researched through here and didn't see the specific situation that I'm facing, which I find odd that I'm seeing in both places.

Home: - iMac 2016 (Sierra) - MacBook 2016 (Sierra) - Airport Extreme, functioning as both a router and a backup device

Small biz: - iMac 2016 (Sierra) - iMac 2013 (Sierra) - iMac 2009 (El Capitan) - MacBook 2016 (Sierra) - Airport Extreme, functioning only as a backup device -- as a NAS drive - Generic router

At home, Computer is able to surf the Internet -- but it does not "see" the drive in the Airport Extreme. This is odd because they're the same hardware! At small biz, exact same error, it doesn't see the NAS drive.

Other observation: - Finder shows the Airport under "Shared", but the icon is the same as what it would look like if it was a PC (the square box with the blue screen ) -- not the icon that one would usually see, one that looks like an Airport Extreme. - Disk Utility does not see the drive

What I've tried: At Small Biz, using iMac '16 and disconnected it from the backup (Select Disk -> Remove Disk). I got the IP address (arp -a) and connected it via Finder (Go -> Connect to Server -> afp://xx.xx.xx.xx). At this point I was able to see the drive under Shared (now with Airport Extreme icon). I could see the historical backups via Time Machine.

Same steps with same results on all other machines.

Why this isn't a workable solution: 1. After spot checking the backups, I forced it to "Back up Now". TM errored out and forced a complete backup of iMac (ouch). 2. TM is now looking for a specific IP address, not a drive. I assume this is going to be a problem if the router reassigns IPs. 3. I assume that, if #2 happens then #1 will follow on a recurring basis.

Any other ideas of what to try?

  • It may be a good idea to use the Bonjour Name of the device, which may be found at your MacOS Preferences, under Sharing in the text box "My-iMac.local" or "My-MacBook.local" instead of using the IPs. As for the router IP, it shouldn't change. It is the only static IP on a DCHP network. (It should be something like and it will never change unless you mess with it) – bret7600 Mar 7 '17 at 13:51

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