Resolved MacOS 14.1.2: Time Machine not working reliably after update from 13.6.1

[a.borque]

Hello!
While I had planned to stay on 13.6 ff a bit longer an automatic update recently pushed my MBP 16 to 14.1.1.
Since then Time Machine is not working as expected. It says something like "Searching for backup volume" or "Connecting to backup volume" and then does nothing. After a while the circled arrows (the Time Machine icon) appear with an ! . Sometimes it works though.
The target device (a NAS) is always reachable and I have not changed anything in my network, the update to from 13 to 14 is the only change.
Updating from 14.1.1 to 14.1.2 did not help.
Is this a known issue that I haven't found in my Google and forum searches? Are there any tips that might help?

 

[Bigwaff]

What brand NAS device and is the TM volume shared using SMB or AFP?

 

[a.borque]

It is a Synology DS214+ running DSM 7.1.1-42962 Update 6. The share is available using SMB and AFP. Neither DSM version nor any settings were changed. The only difference is the jump from MacOC 13 to 14.

 

[Bigwaff]

But are your clients using SMB or AFP to access the share? You should turn off AFP. Apple no longer officially supports AFP.

Apple removed support for AFP. What file service should I use to access files on Synology NAS? - Synology Knowledge Center

Synology Knowledge Center offers comprehensive support, providing answers to frequently asked questions, troubleshooting steps, software tutorials, and all the technical documentation you may need.

kb.synology.com

Unfortunately, there are issues with SMB and Sonoma.

 

[RondoReggie]

I've found that every major macos-update breaks my timemachinebackups for the last few years. Very frustrating. I even anticipate this now, and take it into account that I have to fix this post-update. Yesterday I updated from 13 to 14, and low and behold; this time it is not broken! (yet...)

I made some notes for myself after troubleshooting and diagnosing these issues every time. My quickest fix is: from within macos settings delete the backup destination, discard the data, en create a new backupjob. (don't use 'existing disk') If I remember correctly this preserves credentials and share location. PSA this completely deletes all timemachine history, and starts a fresh backup which can take a long time.

 

[a.borque]

According to tmutil, my Mac used AFP for TimeMachine. So I disabled AFP on my Synology NAS, enabled "Announcement for TimeMachine via SMB" (SMB v2 and v3 are allowed), deleted my old destination in the MacOS settings and set up a new one (according to tmutil it's SMB this time). I did not delete the old backup data there, but instructed TM to continue using it. Then I manually triggered a new backup run and it worked. I hope the automated backups will also work. If not, my next step will be to delete my old backups and create a new one.

 

[a.borque]

A short update: everything, including automatic backups, continues to work as expected.