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What causes TimeMachine backups to fail on NAS devices?

The newest fun part: with the latest update the network connections with enabled Firewall are stable, but if you backup your Mac with TimeMachine to a NAS device, the backup is no longer working. Stops between 200 and 400MB.




[Re-Titled by Moderator]

MacBook Pro 16″, macOS 15.0

Posted on Oct 4, 2024 4:35 AM

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Posted on Oct 5, 2024 6:29 AM

I back up to a Synology NAS using Time Machine and it worked yesterday and not today after 15.0.1 update

"The network disk disconnected from your Mac while backing up."


Mine gets to 0MB. But with a film playing off the same NAS during backup gets to 95 MB then goes to 'skipping'

96 replies

Oct 12, 2024 12:06 PM in response to nuclidefuse

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.

Oct 12, 2024 12:53 PM in response to matthias260

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.

Oct 18, 2024 3:09 PM in response to matthias260

This isn't just NAS's. I have two Mac Mini's and an MacBook Air. The Air is a M2 running 15.0.1 on of the Mini's is a M2 running 15.0. The third Mini is the target and it is older. It is an i7 running 10.15.7. All it does is act as the target and has worked for years until this update. The 15.0 machine works fine the 15.0.1 machine, no dice. I have gone as far as completely reformatting the target drive and reconnecting the Air to it. The connection is initially made and the sparse bundle is created but then the backup goes into the abyss and I get a failure that says the remote disk disconnected.


I am yet to look into the firewall fix that people have been talking about but this as someone said is a complete dumpster fire. Apple has really dropped the ball with 15.0.1. That 15.0 machine isn't getting the update anytime soon.

Oct 19, 2024 3:06 AM in response to NBT123

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.

Nov 12, 2024 2:11 PM in response to matthias260

In MacOS 15.1 is more broken in Time Machine for use with NAS


When removing and adding back the NAS to the Time Machine devices:

  1. Time Machine shows you all folders even though they are not designated Time Machine folders - it shows all folders that are currently connected to the Mac, whether or not marked as Time Machine folder.
  2. the dialogue, where one is supposed to enter the logon data of the credentials of the NAS cannot be edited. It is prefilled with the user of the MacOS, but you can enter only one letter from the password. At least you can add credentials that you have saved in passwords, but if you haven´t saved it in passwords, you cannot enter anything.

Currently only backups to external hard drive continue to work.


Error message: "The network disk disconnected from your Mac while backing up"

  • With Synology NAS is no backup is possible,
  • backup old Time Machine settings fails (running in the same setup since 2018),
  • switching off firewall no longer works.


What causes TimeMachine backups to fail on NAS devices?

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