TIL: Apple Broke Time Machine Again on Tahoe
taoofmac.com
taoofmac.com
edit: I use Arq for daily backups, but T.M. for hourly. When T.M. eventually craters its storage, I have robust dailies in the cloud, so no worries.
The problem is them fucking up. Every other popular backup solution that does it does it just fine. And doesn't hide failures silently
As opposed to what? When you need to be able to back up to a drive on your network?
I'm sure you could do the same with cron and rsync, but I can't be bothered.
[1] https://shirt-pocket.com/SuperDuper/SuperDuperDescription.ht...
I could probably setup a calendar appointment to dump a bootable image once a month to an external disk.
While I agree that SuperDuper! is worth buying, it is free to use for whole-disk backup/cloning. The paid version enables smart copying (that is, only copying files changed since the last backup).
Edit: Yeah, the bootable backups have saved me more than once. It's great to just be able to keep working even when the system disk is kaput.
Well as long as Apple hasn’t broken that with an update: https://www.shirtpocket.com/blog/index.php/shadedgrey/youre_...
An initial backup on newly formatted disk will run but very slowly. Perhaps reaching 100% but it never finishes. At some point the percentage will change and the backup will stay stuck at somewhere near 10%. Cancel backup and run it again. Gets to ~10% and stays stuck. Multiple drives. Re-fs'ed. Boot into safe mode. Networking off. Etc, etc. etc. The TimeMachineMechanic app doesn't have any revealing feedback. I can run a full tar backup to the same disks.
No idea.
I haven't tried backing up to a network share but really, it shouldn't be this difficult.
Clearly someone didn't test a bunch of edge cases when pushing this one out.
log stream --predicate 'subsystem == "com.apple.TimeMachine" AND NOT (category == "LogLimits" OR category == "VolumeViewModel")' --info --debug --style compact
man log
man tmutil
Some things to look out for are what filesystem your newly formatted external volume is (APFS might not be great for a single spinny disk, for example), and what version of USB is in use (friends don't let friends do USB 2 mass storage). With inexpensive external media it's often a cable or power supply issue, even if (as in your case) tar appears to work. Have you checked that the contents of the tar file are correct? Also, tar files tend to be streamed out to sequential LBAs, where smaller files and (in Time Machine backups) holes might lead to a different write pattern that the drive might not like. Maybe test with rsync -c instead of tar?
There was a time in the past when Time Machine was reliable and well-designed. It made backups into a nice experience that were accessible to everyone.
If your only experience with Time Machine is the modern incarnation with all of the flaws and seemingly missing QA process then I understand how its popularity would be confusing.
1. There was a small, smart team which made time machine in the first place. They did good work. Building time machine required some pretty deep integrations into macos that not many people understood.
2. Years passed. The people who built time machine moved to greener pastures. At google and samsung you mostly get promoted for releasing new products. Not maintaining old ones. I wouldn't be surprised if its the same at apple. Over time, the people who made time machine left and were either replaced by more junior developers. Or weren't really replaced at all.
3. Random changes in the kernel break time machine regularly. Nobody is in charge of noticing breakage, or fixing it. Most people who care (and have the knowledge to fix it) have moved on.
I find things like this so odd from an organisational management perspective. Do companies not realise that features like time machine would have an ongoing maintenance cost? That someone would need to check that time machine still works with every release? Or is it just vibe based management out there? "I guess nobody works on that, and we don't test it. Oops whatever."
I assume many managers resist this temptation, but someone yields with regularity.
… so I’ve been kind of biting my tongue on this thread because “works fine for me” is not interesting or helpful, but: it’s been working great for me since it was introduced in 2007.
Periodically a disk will get flaky or go bad, maybe once every 2-3 years. I’ll erase the drive and start over. I always have two backups running so there’s never danger of being completely unprotected.
I don't doubt the people having Time Machine problems, but they usually seem to involve some unusual setup like a NAS. But for every one person who has a problem and speaks up, I suspect there are hundreds or thousands who are just humming along without a hitch.
(and yeah, I do pray for a "Snow Tahoe," "oops all bug-fixes" MacOS release, and I’d love to hear that there’s a team working not just to make Time Machine more resilient, but to expand it to do local backups of iPhones and iPads… a guy can dream)
> … so I’ve been kind of biting my tongue on this thread because “works fine for me” is not interesting or helpful, but: it’s been working great for me since it was introduced in 2007.
Is immediately contradicted by this
> Periodically a disk will get flaky or go bad, maybe once every 2-3 years. I’ll erase the drive and start over. I always have two backups running so there’s never danger of being completely unprotected.
Having to periodically erase the drive and start over is one of the problems we’re talking about.
In my experience, restoring files gets flakey before it reaches the point of having obvious backup failures so you may be experience more problems than you know about if this is happening periodically.
I have since implemented a borg backup. This also failed at one point, but at least its five-year record remained readable, so no data was lost. Now I'm using restic.
It has its flaws, but any system is better than no system at all, which is usually the trade off that would be made.
That's why I like it. Some of the visual flare is of course superfluous, but the timeline really is nice.
It's like git except it works without me having to think about it. (To be clear, git is much better, but I have to think about it.)
Also, backups over the network are possible and have worked well for me for a few years.
From what I can tell, this snapshot is preventing space reclamation. The last month or so, I've constantly run out of disk space even when not doing anything special. As in actually run out of disk space — apps start to become unresponsive or crash, and I get warning boxes about low disk space. When you run low, the OS is supposed to reclaim the space used by snapshots, but I guess it doesn't happen,
The stuck snapshot can't be deleted with tmutil. I get a generic "failed to delete" error. The snapshot is actually mounted by the backup daemon, but unmount also fails. The only solution I've found is to reboot. Then I get 200-300GB back and the cycle starts again, with snapshots getting stuck again.
I'm considering updating to Tahoe just because there's a chance they fixed it in that release.
I think I have the same problem on Tahoe.
On the extremely rare occasion I have to replace my laptop, I literally just point it to the backup on the network with the cable plugged in, and an hour later it's "my laptop" again.
But, I haven't installed Tahoe. I may skip it entirely, hoping that they do a Snow Leopard-like clean-up-the-mess release in September.
Apple really needs to turn things around.
Yosemite > El Capitan > High Sierra > Big Sur > Ventura > Sequoia
I won't be installing Tahoe for the time being. Hoping macOS 27 will be an improvement.
Something like [1] can be inspiration.
If I had to start over I'd go with rustic-rs or borg backup.
FWIW I do still use `tmutil localsnapshot` for local macOS snapshots where you can use the Time Machine UI to restore files.
It's the same on macOS and iOS, pick "macOS Sequoia Public Beta" or the corresponding release for your device. Apple still pushes security updates for those releases, and I haven't heard of any problems with the kind of minor updates that ship late in a major release's lifecycle, so I think the risk of running this way is low. This kicks the can a year or two down the road, at which point hopefully there are better workarounds.
Apple should document such changes, but, looking at the post title, you'd think they were silently corrupting data during restoration.
I'd argue that's not even the main problem. If it just broke and gave you error on each run ("this SMB share is incompatible") it wouldn't be an issue
> Time Machine backup to NAS devices over Apple Filing Protocol (AFP) is not recommended and won't be supported in a future version of macOS.
https://bombich.com/blog/2024/12/19/bootable-backups-have-be...
mbentley's Docker image version of Time Machine—which I began using back when native Time Machine support was completely broken <https://www.reddit.com/r/unRAID/comments/16x3ddm/my_experien...>—which the post mentions is unaffected, and continues to work with Tahoe without configuration changes.
For a professional devops person managing a custom backup solution, I agree.
For someone using mainstream consumer technology on a consumer laptop, it's not realistic to expect this. It needs to just work.
However, I have lost data in my lifetime. If you value your backups, check on them.
Also, if you're the kind of person who has a Synology, it means you had to buy a NAS, drives, and setup all the associated machinery for Time Machine over your network. Therefore, I feel it's not outside of the expectation that you can check on your backups. Even if it's just a quick test of a restored file or folders.
I don’t understand why people think this is complicated or limited only to highly technical people.
NAS units are popular with consumers now, not just tech people. They buy them with drives installed and they come with instructions to set up backups with Windows and Mac.
I would imagine a more typical consumer would be buying a USB or Thunderbolt connected drive and following the prompts to set it up.
My impression is that companies like Backblaze and other backup-as-a-service solutions are more consumer-popular because it externalizes the complexity and pitfalls like the author is experiencing.
The problem is that the typical consumer with a laptop never uses it in a docked configuration and just plugs it in to charge.
You may as well tell someone they need to regularly plug a USB hard drive into their iphone to back up their photos.
Mounting an SMB share on a Synology NAS to use as a Time Machine backup target is not what most users would consider "consumer technology."
Your umbrance is with Synology, not Apple.
Apple raised security default configurations in Tahoe. That led to a config breakage with NAS devices which rely on relaxed security configurations.
I agree Apple should publish a technical note / changelog of config changes such as this one, but Apple has never implied to users they'd carry a support burden for any/all third-party hardware vendors. To the contrary, they've notified users that you're meant to consult with your NAS vendor for configuration steps:
> Check the documentation of your NAS device for help setting it up for use with Time Machine
I was just replying to your point that a Synology NAS "is not what most users would consider 'consumer technology.'" It's firmly in the consumer technology category.
The consumer NAS business is large. These are popular items with average consumers who understand the importance of backups.
It’s reasonable to expect it to work properly.
Regardless he should've gotten alert if backup target is unusable, not silently break
My biggest gripes with Time Machine are the lack of visibility, the silent failures and the inflexible scheduling. I know there are methods to work around the last one, but the first two are paramount. It does do consistency checking, at least as far as the logs say, but it says nothing about the health of the backup container.
While most users don't really want to know about this stuff, I feel like it's important enough to have a more comprehensive UI to provide some insight into the feature and the associated health.
It’s long past time you flipped the bozo switch on Apple, the title of your blog notwithstanding.
Most computers Apple sells are laptops. By a huge margin.
So what am I supposed to do? Put my laptop in the same spot every night, plug it in, plug in the drive, and then the next morning carefully make sure the drive is unmounted before I move my laptop anywhere?
That’s kind of ridiculous. Network storage works. Apple has supported it for years.
If they don’t want to support this, don’t let the OS do it. Until then, don’t break my backups.
Time Machine is absolutely for the layman, and something I feel can be improved upon with a bit more visibility in to the status.
If you want to backup across the network then it’s probably best to choose some third party software.
As an experiment, open Console and filter just errors and faults. Dozens to hundreds of “errors” will scroll by representing the normal operation of the system. (Either they’re not really errors and no one cares or they really are errors and Apple just leaves their systems broken). How can anyone think this is OK?
I haven’t upgraded to Tahoe. I have been a Mac power user for over 20 years, and it becomes less interesting every release. I came for Unix, the script ability, and 3ᴿᴰ party applications. Unix is an afterthought, script ability is all gated behind security gates, and modern apps seem like such a huge regression.
"Does this increase iCloud subscriptions or not?"
1) Every team does something different because none of them talk to each other. There are very few horizontal programs across engineering there. As a result, processes and results vary greatly.
2) They're very "traditional" in many ways. They're not a fast moving engineering led company, they're a slow moving business and marketing led company. Engineering is not their secret sauce (except perhaps some bits of hardware engineering). They are sometimes the sort of org that says why both with automated tests when we have a QA team.
With third party stuff, maybe you'll get lucky, but no guarantees...
3rd party monitors, or keyboards, or mice (what's a mouse?) or ...SMB devices
Not as nice UI-wise, but at least it's stable
Also, I don't even have an /etc/nsmb.conf or /etc/smb.conf file on the mac ( Tahoe 26.3)
I think the last time I configured Time Machine for SynologyNAS I followed as many tutorials as I could and basically everything is working for both mine & my spouses machines. - until it crashes & I lose everything.
Then again, SMB especially in its newer versions seems to be a protocol developed by MS with one of its goals being to make third-party implementations as difficult as possible.
- Enable Apple SMB2/3 Protocol Extensions
And when creating the SMB share select Time Machine for purpose.
- i am too afraid to buy another one and connect only to find out the SSD gets killed in another week
- Anyone knows about this issue?
Also you'd want the SSDs to be much larger than what you need to backup. If they're small, then time machine will have to erase the older backups to make new backups, which just leads to more rewrites, stressing the SSD more. The ones I used were 4TB, but a clean first backup of my system was only like 250GB (because many things excluded). And then daily incremental backups are like 1-3GB.
Reliable for me is Kopia from Mac to S3 compatible volume (minio) on Synology.
The backup system that silently breaks when it doesn't like something in backend is not worth time
Look, face it, Time Machine is not really what Apple wants you to do. They want you to buy cloud storage and just store your documents (desktop and documents in iCloud Drive) there. Photos are in the photos app. Etc.
Maybe they should make a Time Machine cloud service to help them justify putting time into it just like iOS has cloud backups, which work incredibly smoothly. But it’s also possible macOS has too much baggage for that to work (then again, migration assistant also seems to work great.
Long story short, if you want this you probably should be working with a third party, something like tossing $5 a month at backblaze backup.
I’ve moved away from Mac and I’ve been having a great user experience with Pika backup, although it’s not quite analogous to Time Machine. Still, my Linux distribution is immutable, so backing up my home directory is pretty much the whole thing.
The last straw is that Finder's scroll bars are broken in Tahoe. I put up with it until I hit an emergency at work and was working as fast as I could (each minute mattered), Tahoe was slowing me down. Tahoe didn't pass the pressure test.
Yeah, this is most I’ve regretted updating macOS in a decade. Apple Music in Tahoe is no longer capable of playing LAN-shared music without bugging out, which is a real bummer for my normal workflow of listening to music all day while I work.
Plasma on Linux is looking pretty tempting these days, especially with almost all office software being web based these days.
Switching email clients is a big lift that I need to investigate, and have been hesitant to jump into until absolutely necessary, but another week of this BS...
https://www.jwz.org/doc/backups.html
You can also get any AI tool create a good backup script for your particular setup.
Supposedly, doing that eliminates a lot of the flakiness specific to SMB Time Machine, and while I haven't tested it personally, I have used disk images over SMB on macOS Tahoe recently, and they actually work great (other than the normal underlying annoyances of SMB that everyone with a NAS is mostly used to at this point).
The new ASIF format for disk images added in Tahoe actually works very well for this sort of thing, and gives you the benefits of sparse bundle disk images without requiring specific support for them on the underlying file system.[1][2] As long as you're on a file system that supports sparse files (I think pretty much every currently used file system except FAT32, exFAT, and very old implementations of HFS+), you get almost native performance out of the disk image now. (Although, again, that's just fixing the disk image overhead, you still have to work around the usual SMB weirdness unless you can get another remote file system protocol working.)
[1]: https://eclecticlight.co/2025/06/12/macos-tahoe-brings-a-new...
[2]: https://eclecticlight.co/2025/09/17/should-you-use-tahoes-ne...
Mount something over NFS< and you'll be relieved about how snappy things remain. Snappy relatively of course.
Yes, there's some bug in the backupd that panic.. no matter smb/nfs
Using unauthenticated NFS, even on a local network, is too dodgy imo.
Sometimes, Time Machine just goes stupid and I have to wipe the drive and start over. All of my efforts in the past to copy or repair or do anything to a Time Machine drive has ended in folly, so when it starts acting up, I just wipe it and start anew.
Other times, it's the drive itself, and I swap it out.
99% of the time, it Just Works. Wiping the drive for me is more annoying than catastrophic (99.9999% of the time I don't care about my 18 month old data). It's mostly for local catastrophic fat fingering on my part, and to make sure I have a solid back up after I do a OS update. I have BackBlaze for "Why is there 5 feet mud in my burning house" scenarios.
Outside of that, I've always been able to recover from it.
My wife has a SSD drive she plugs into her laptop for TM backup. That machine at most makes laps around the house, so its not that big of a deal for her.
The bar is so low!