I have just upgraded my 2018 Mac Mini to MacOS 15 Sequoia.
Since 2019 it has always backed up to a folder called TMFolder on a Synology DS413j.
( My partner's Mini also backs up to the same NAS, but hers is still on Sonoma. Her backups still run successfully. )
Every time Time Machine on my Mini tries to backup to the NAS now, it reports:
The backup will fail anywhere between one and five minutes after starting.
Mac mini, macOS 15.0
Apple is not to blame if the Synology Server does maintain a proper TM handshake. Synology doesn't use a licensed version of Apple software. They are forced to use a public domain version of AppleShare that may simply not yet be compatible with a new major release of macOS such as Sequoia. That puts Synology in a bind too.
There are things that one must handle in the Synology Diskstation configuration settings too such as keeping current with DSM 7.2.2 and ensuring that in Control Panel > File Services you are using SMB 3. Synology has this Mar 4, 2024 article on Time Machine though that may not be enough if there is an incompatibility lurking.
I have a new DS119J downstairs with DSM 7.2.2 and 16 TB configured and I still don't attempt TM backups to it. Otherwise, file sharing works just fine with released Sequoia v15.0.
Update 29th Oct: After updating to macOS 15.1, I'm able to backup to my NAS with Time Machine without issues (with Lulu and firewall enabled).
Same issue: Mac mini 2020 M1, Sequoia 15.1, Synology NAS
When this still didn't work with the updated MacOS 15.1 and turning the Firewall off, I tried a different tactic.
I shut down the Synology NAS
In Time Machine I selected a manual back-up. Time Machine responded that it could not find the server.
Restarted the NAS.
Again selected a manual back-up in Time Machine.
After some time "preparing the back-up", the backup actually began....and completed!
The Firewall was active the entire time.
What worked for me:
Not sure which of these is an actual fix, but 1+2 definitely didn't help. Only when I did 3 it started backing up.
Still on Sonoma but recently had this issue - 3 different laptops all kept giving same failure to Synology NAS Time Machine backup. Eventually just had to delete that TM setup, start as new and works on all now.
Don't bother, had it since macOS 12 in combination with DSM6.x and today with macOS 15 in combination with a brand new DS923 running DSM 7.x same issue. Finder loses connection with Synology NAS (and also TM). When will Apple crushes this bug finally? In version 20? Djeezzz.
When will Apple crushes this bug finally? In version 20? Djeezzz.
It’s not an Apple bug. It is a Synology bug.
Prior to their SMB 3 implementation, they use Netatalk which is a hack of Apple Filing Protocol (AFP). Apple has never licensed AFP. When Apple switched to SMB networking, they set a specification for Time Machine over SMB. It is up to Synology to support that specification.
Locally macOS 13 and macOS 14 are working with Synology configured for Time Machine Server. DSM 7.2.2 with update. Testing included full restores.
Here is the Synology NAS setup (also linked in a reply above):
If it is still not working, I’d suggest updating to current DSM if not already, and then asking this question again over in the Synology forums: https://community.synology.com/enu/
No macOS 15 in production yet (locally), so no Synology TM support testing (here).
Problem with Synology is back. After working fine for one day. It doesn't matter whether MacOS firewall and Objective-See apps are disabled, Time Machine cannot connect to the NAS, although Finder has no problem.
spoona wrote:
Problem with Synology is back. After working fine for one day. It doesn't matter whether MacOS firewall and Objective-See apps are disabled, Time Machine cannot connect to the NAS, although Finder has no problem.
All of the add-on security apps — all of the add-ons — removed per vendors’ instructions, restarted, and tested again?
This then tested with current DSM on the Synology?
If so, let Synology know, if they don’t already.
Similar issue here on an iMac Pro running Sequoia and a Synology DS218j with the latest Desktop Manager 7.2.2-72806. The Synology is not reporting any problems.
My Time Machine backups initially worked after updating the Mac, but have now repeatedly failed and I haven't been able to get them running again. I've even created a new backup folder on the Synology to see if it is an incompatibility with previous backups.
I can get the backup started after a very long 'Preparing to back up...', it finds the changes and then begins copying files to the Synology, however it stops abruptly before being completed and never gets to the cleaning up stage.
I don't get any sort of pop-up alert warning, nor does the Mac itself say the Time Machine drive has disconnected, but the little red error symbol gives the same Time Machine error you're seeing about the disk disconnecting whilst in use. The drive remains mounted on the Desktop and in Finder.
Trying to Verify backups through Time Machine also results in the same error.
I've tried rebooting the Mac and the Synology but the error persists.
I wasn't getting this issue before the update to Sequoia, so something behind the scenes has definitely changed. Unfortunately, Time Machine's rather terse messages about what it is doing aren't helping me see where exactly things went wrong.
I fired up TheTimeMachineMechanic after a failed backup and its results are:
Analysis from 2024-09-21 12:22:24 +0100 to 2024-09-21 14:22:24 +0100 for 2 hours:
Backing up 1 volumes to Backups of Hekla (/dev/disk3s1,TMBackupOptions(rawValue: 0)): /Volumes/Backups of Hekla 2 on which there were 3.93 TB, 3.93 TB available.
Current free space on backup volumes: 0))
No auto backups started in the period, no backup has been completed successfully in the period,
Created 0 new backups, and deleted 0 old backups,
Created 1 new snapshots, and deleted 6 old snapshots,
Of 0 volume backups:
0 were full first backups,
0 were deep scans,
1 used FSEvents,
0 used snapshot diffs,
0 used consistency scans,
0 used cached events.
✅ No error messages found.
⚠️ Running check on scheduling system (CTS and DAS).
DAS appears to be rescoring normally over the last 90 minutes.
Running CTS check next.
CTS has not been told to run a backup in the last 90 minutes. Scheduling may have stopped.
Consider restarting your Mac.
Hopefully this is a teething trouble from a new OS release, but I might need to attach an SSD as a temporary backup drive until the issue is resolved by either Apple or Synology - though I think the only drive I have spare is one of those potentially flaky SanDisk portable drives :(
spoona wrote:
I have just upgraded my 2018 Mac Mini to MacOS 15 Sequoia.
Since 2019 it has always backed up to a folder called TMFolder on a Synology DS413j.
( My partner's Mini also backs up to the same NAS, but hers is still on Sonoma. Her backups still run successfully. )
Every time Time Machine on my Mini tries to backup to the NAS now, it reports:
https://discussions.apple.com/content/attachment/210afe65-c27a-4054-a7f0-293a6a494cf0
The backup will fail anywhere between one and five minutes after starting.
Thanks - just checked and it was 'On' on my iMac Pro.
I've flagged the issue to Synology and their automated response suggested clearing all the SMB caches on the Synology Control Panel. But that hasn't fixed it, I've told them this hasn't worked and will see if they send a more detailed response later.
Just wondering - OP and myself are both running Sequoia on Intel processors and getting failures. My M2 MBA is backing up to the same Synology without issues.
Is anyone getting this fault on Apple processors?
I'm experiencing a similar issue. Time Machine backups occasionally fail, and file transfers to my NAS over SMB frequently cause my Macbook to disconnect from the NAS.
MacBook: Apple M3 Pro MacOS 15.0 (24A335)
NAS: DS918+ DSM 7.2.2-72806
Thank you for posting your experience. so you essentially re-did the macOS<>synology time machine integration and it's still not working the same as it was prior to the update from sonoma to sequoia? new folder, proper time machine folder settings, create the new time machine backup, etc... you did all that and it's still not working? ughhhhh
For me, that's always been the workaround that i've found solves these problems after a new macOS update. When macOS updates, can't think of a year that I wasn't forced to completely reintegrate time machine with my synology. it's always awful every year, but at least it still works in the end... not this time tho?
'Fraid so.
I've chatted with Apple twice now.
The first time they asked me to try and start the iMac Pro in Safe Mode (failed with same error); to create a new account (failed); and reinstalling Sequoia (initially seemed to work, but then it failed overnight with the same error and has failed every time since).
I've chatted with them again and I'm waiting for a call back. First line support is saying they've not heard of this error before, so I have pointed them to this thread.
My MBA is updating completely reliably throughout.
I'll keep people informed.
Sorry to get peoples' hopes up. My iMac failed to back up this afternoon when I was away and gave the same error about the Synology being disconnected.
So the 'fix' doesn't do anything. Don't waste your time if you haven't started.
Synology have asked me to provide them with a log of the failure so, just as soon as the next backup fails I will share the log information with them and with Apple.
Back to my SanDisk SSD for backups!
Sequoia Time Machine Synology NAS keeps disconnecting
