Sequoia Time Machine Synology NAS keeps disconnecting

Updating the SMB Service package to the latest beta (v4.15.13-2319) on my Synology NASes appears to have resolved the issue for me — at least for the time being.

Interesting. And I should add I am running a Macbook Pro M1 so the macOS 15 for Intel seems suspicious.

Wow nice… will be neat if I don’t have to delete my backup history every year. Thanks for posting that!

Update: No. 15.0.1 did not solve the problem. The problem re-occurred today.

I installed the recommended Synology beta for SMB and my backup continued to fail. The only workaround I've found to work consistently is to turn the firewall off.

Simply go to System preferences, Open the Network item and in Firewall, toggle it to off, and your backups will work. Of course, it's not ideal if that's the only firewall protecting your machine.

I'm running 15.0.1 with firewall turned on, but my TM backup is still failing, if you turned it off, it will work, but not ideal. Anyone figured out how to get it back working with firewall on?

As disabling Apple's firewall seems to fix the issue, this is clearly not a Synology problem to fix.

Apple did some changes to the firewall settings that are causing the problem.

After additional days retrying backups, only way to get them succeed is disabling the Firewall

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.

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.

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?

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!