What causes TimeMachine backups to fail on NAS devices?

In my case after update to 15.0.1 the "preparing to back up" step takes 30-50minutes...

Before update it was up to 3-5minutes max!

The backup step itself is quite fast as usual.

I have SMB QNAP Network share.

Disabling the Firewall , new TM setup, delete a few latest backup did not help as well...

I'm on 15.0.1, too, but the TM backup was not working correctly. I turned off the firewall, but the problem persisted. Then, checking, I uninstalled my KTS antivirus completely because this software adds a config in the firewall; I think for it to work correctly and filter some network traffic, this and a restart, the backup started working up.

Metoo here after 15.0.1 update. Read that turning off is a temp solution. However. I have a company laptop where turning off firewall is greyed out. So no option for me.

I truly hope Apple will fix this issue. This is a serious problem!

So for the second day, after getting TM to work with the FW off, I tried to backup without turning it off. And it failed. I even added the TM app to the rules of FW to accept incoming connections. But that didn't work either, it said the external disc had disconnected. So I turned off FW off again just for TM and it worked perfectly. This is an error introduced by Apple in 15 or 15.0.1. I will have to turn on and off FW just to get TM to work - how annoying.

It appears it is not just TimeMachine backups to SMB shares. VPN's, RDP connections, DNS lookup requests, 3rd party network security products etc.

Suggest everyone uses the feedback tool on their Mac's and report the issue, that is what that tool is for.

Lets us hope an update fixes this quickly, I can imagine quite a few systems will be affected.

Adrian.

I bought a new M3 MBA, installed 15.0.1 and migrated an old Intel MBA to it. T-M backups failed. Rather than go the long haul route, I shall downgrade the M3 to Sonoma 14.7.1 and reinstall.

Meantime, I've reported this direct to Apple executive relations.

I'm going to try adding time machine to the exempted apps on firewall settings and see what happens; that would save turning firewall off and on for backing up, even though I also run an intego firewall - and have done for years without any issue for time machine. Like everyone else 15.0.1 has tripped the issue; partner's still on OS 14.6 and working fine to the same backup device.

Even though AFP is not listed as a way to connect to a NAS drive for Time Machine, I did exactly that--turned on AFP on my Synology DS218J NAS, connected to the server via AFP, and *I think* I selected the AFP-connected drive designated in the Synology settings for the Time Machine backups, and so far I'm 10%/10 GB into the initial backup with the firewall turned on.

I'll have to do some more experimentation, but connecting via AFP may be a workaround.

At least I think I'm using AFP...I turned it on in the DS2J settings, then when connecting to an external server I typed in "afp://ds218j.local:5000" and it connected to all the shares on the DS218J. I set up Time Machine to the "Time Machine Backups" share, firewall on, and the backup is progressing...14%/28GB, five hours to go over wifi.

I may try turning off SMB on the DS218J (after the other Macs in the family do their backups) and see if it still works on my 15.0.1 MBA.

To add my tuppence worth, it’s more than just backups.

if you search you will find it looks like the Mac’s ability (or lack of) to communicate properly with devices on a local network.

I’ve had issues with RDP connections to machines on my local LAN, VPN issues into my local LAN and have seen reports of app developers struggling to get their programs to pop the “allow access to local lan?” message and I’ve also seen reports of DNS queries failing if the DNS server is on the local LAN.

Agreed it is really terrible and shoddy testing on the part of Apple.

These are not budget devices we invest in and I expect a bug as big as this one to be caught so early in the testing process so as not to appear in the public release.

I have fed back to Apple with my diagnostic logs.

Mine stuck at "connecting to backup disk..." and the log just said "Bonjour resolution not possible for 'afp://backupworker@x.x.x.x" indefinitely. Apparently I'm able to mount the AFP volume in Finder or `mount_afp` and I can tell Bonjour broadcasting works just fine, but the Time Machine just can't.

Im having a similar issue. We use a Synology Nas to edit footage from. Its been fine for near on 2 years. I updated (mistake) 2 weeks ago and then all of a sudden monday monring the server is disconnecting whenever it needs to do something ie: Exporting a video, reading the timeline, importing photos. It doesnt seem to matter about the file size. It just disconnects. Any ideas here? its only an issue with the NAS. Other drives like the Black Magic Cloud unit is fine. Also transfer speeds have slow right down

This is what I'm trying. Downgrading back to 15.0 per support page. How to download and install macOS - Apple Support