macOS 27 does not support CoreStorage volumes

(wadetregaskis.com)

113 points | by colejohnson66 6 hours ago ago

63 comments

  • Marsymars 3 hours ago ago

    Well, heck.

    I posted ~7 months ago about my decision to use HFS+ for backups, and had a couple skeptical replies. (https://news.ycombinator.com/item?id=47317123)

    I guess I misjudged Apple's commitment to support HFS+ long-term.

    It now seems like there's no real native way of doing encrypted backups to HDDs on macOS (APFS not really recommended for HDDs)... the options are either encrypted Time Machine to a network location, or a third-party tool.

    Guess I'll figure out SuperDuper or Carbon Copy.

    • lakeviewterrace 2 hours ago ago

      > encrypted Time Machine to a network location

      this has a bonus feature where it will slowly corrupt itself over time and offer to start a completely new backup instead.

      • thfuran 30 minutes ago ago

        Sometimes it's pretty quick.

    • AceJohnny2 an hour ago ago

      > I guess I misjudged Apple's commitment to support HFS+ long-term.

      One thing I have learned with (current) Apple is to never trust their commitment to support something they're not using. And even be wary for stuff they are using. (in my mind, a core technical difference between Microsoft & Apple is that MS will bend over backwards for backwards compatibility, whereas Apple will drop it as soon as they can, and sometimes sooner still)

      They replaced their use of HFS+ with APFS in 2017, so it's had a good run.

      • AceJohnny2 an hour ago ago

        I have heard from ex-CoreOS (the Apple org) colleagues is that the organization is run intentionally lean, because the leadership believes that people do their best work under pressure. This leads, among other things, to aggressive YAGNI pruning.

      • unsloppable 8 minutes ago ago

        Rosetta..

    • qmr a minute ago ago

      ZFS

    • stingraycharles 2 hours ago ago

      Ok I may be an idiot, but I just have a permanently attached external disk that does Time Machine, what am I missing out on? Why network location? Or are you backing up massive amounts of data? (for me it’s just 2TB)

      • Marsymars an hour ago ago

        Oh right — I could do a local HFS+ non-encrypted disk with encrypted Time Machine (I assume) — that just slipped my mind.

      • root9876 an hour ago ago

        I switched to Borg on Linux server from local attached Time Machine disk after once I went to a long trip and forgot the disk at home.

    • mrpippy 3 hours ago ago

      I don't think APFS was designed or tuned with HDDs in mind, but it will work just fine. Especially for backups where random read/write performance is not important.

      • MilaM 3 hours ago ago

        I would not recommend using an APFS formatted HDD for Time Machine. It's painfully slow. With my Samsung T7 the hourly Time Machine backups are usually finished after a couple of minutes. Using my older HDD they can easily take 20 minutes to half an hour.

        • outofpaper 3 hours ago ago

          While time machine used to be snappy on HDD it was build out of one of the weirdest little hacks hard links in folders. The new Time Machine might front a similar front end but under the hood its a different beast. You're having to mount snapshots as you move through time.

        • fl0id 3 hours ago ago

          are you sure that is because of apfs? hdds are usually much slower, no?

          • zimpenfish an hour ago ago

            It's definitely APFS. I've had the pleasure* of HFS+ and APFS on the same external HDD and APFS is horrible. Given it is optimised for solid-state drives[0], it's understandable there'd be some slack but it is absolute horse paste.

            (If I could create an encrypted external HFS+ volume, I would but macOS hasn't allowed that for a while as far as my experience goes - it's non-encrypted HFS+ or encrypted APFS.)

            [0] https://support.apple.com/en-gb/guide/security/seca6147599e/...

    • isityettime 3 hours ago ago

      Can you use OpenZFS?

      https://www.openzfsonosx.org/

      • barkingcat a few seconds ago ago

        heck no. not for backups.

      • Joel_Mckay 20 minutes ago ago

        MacOS is only Posix like, and does a lot of weird nonstandard things in the background regarding mounting drives/images.

        There are restrictions on where things can run, what can run, and what is accessible to the process.

        SSHFS is slow, but at least can mount windows/linux/android systems over VPN without issues. Look at what is needed to bring up SSHFS or NTFS support, and you should have a better idea of Apples walled garden policies.

        Apple makes information appliances, and not general-purpose computers. Some may disagree, but they usually choose an exception use-case rather than the normal experience of users. =3

  • someonehere 2 hours ago ago

    With macOS 27, I don't know who Apple is trying to outdo?. 27 has been a total disaster for me and my setup at home.

    Back when there was a little more rivalry between Microsoft and Apple, Apple would come up with these really cool things to showcase the operating system and make lives easier. Now, I don't know what it is they're trying to prove with this operating system. I also hate the fact that they skinned the whole operating system around a failed hardware product.

    • lakeviewterrace 2 hours ago ago

      I love when questions like this pop up on Apple's discussion forum, because it doesn't take long for one of their turboshills with 300,000 karma to jump in and tell you it's for your own good and you're just using the computer wrong.

      > I also hate the fact that they skinned the whole operating system around a failed hardware product.

      Apple has always been a marketing-driven company.

      Their market is now TikToking zoomers who don't understand how files and folders work and use their machines to produce videos of themselves eating soap tablets and acting like whores. You're small potatoes to them.

      I remember when Macs used to ship with an encyclopedia preloaded. LMAO.

      • cannonpalms 2 hours ago ago

        Careful, an SNL monologue like that may get you cancelled!!

      • thin_carapace 2 hours ago ago

        uncouth expression , valid point , purpose of a computer is still a tool , we the public r no longer wielders & are wielded instead

        • lakeviewterrace an hour ago ago

          you will operate it for approved uses only — the days of the 'personal' computer are over.

          the future of macOS is the hospital check-in desk in Idiocracy.

  • AceJohnny2 2 hours ago ago

    FWIW, this is listed as deprecated in the Release Notes:

    https://developer.apple.com/documentation/macos-release-note... (Search for CoreStorage; their fragment links are hilariously broken)

    The premier 3rd Party technical blog Eclectic Light talked about it in June: https://eclecticlight.co/2026/06/17/what-to-do-with-your-enc...

    I can't immediately find prior warnings that this was coming.

    The following technical note from July 22nd says Encrypted HFS+ Volumes won't be supported in macOS *28*, so this seems a bit early... https://support.apple.com/en-us/125615

  • hmartin 4 hours ago ago

    Also dropped support for FireWire drives, as I just found out the hard way.

    • traceroute66 4 hours ago ago

      > Also dropped support for FireWire drives, as I just found out the hard way.

      Erm... it was dropped in macOS 26 back in 2025 ?

      https://www.techspot.com/news/108394-usb-killer-dead-apple-d...

      • duskwuff 3 hours ago ago

        And even that was 13 or 14 years after Apple shipped their last computer with a Firewire port - long enough that those computers weren't even supported by macOS 26. Apple dropping support for a largely obsolete technology, which they hadn't used for well over a decade, should hardly come as a great shock.

        • conradev 27 minutes ago ago

          You used to be able to chain three adapters:

          Thunderbolt 3 to Thunderbolt 2 Thunderbolt 2 to FireWire 800 FireWire 800 to FireWire 400

          to plug a modern Mac into an iMac G4 in Target Disk Mode

          Now you need to add another layer: virtualizing old macOS on a modern Mac

        • jasomill 43 minutes ago ago

          Apple's Thunderbolt FireWire 800 adapter daisy-chained with their TB2-to-TB3 adapter should work on any modern system with Thunderbolt and FireWire support, as it just presents as a bog-standard PCI FireWire card.

          So worst-case, you should be able to access your old drives on a modern Mac by booting from a FireWire-compatible OS (Asahi or older macOS) on an external drive.

        • RulerOf 2 hours ago ago

          I had one plugged into the FW800 port of my Cinema Display.

          Only really used it as a scratch drive for junk but it was still handy.

      • conradfr an hour ago ago

        Ah yes 2025, the ancient times.

    • reaperducer 2 hours ago ago

      Also dropped support for FireWire drives, as I just found out the hard way.

      Well, I guess I can finally throw out all those FireWire cables I have "just in case."

      Fortunately, my FireWire drives also support other interfaces, though far more slowly.

    • flanz_10 4 hours ago ago

      did you go from 25 to 27?

  • exabrial 4 hours ago ago

    MacOs 27 is a disaster. All of the sudden, I have 35% of a computer left to do any kind of work.

    • thisislife2 3 hours ago ago

      It's the iOSsification of macOS. Apparently, newer macBooks will now have touchscreen too ... once iPad OS and macOS are fully merged into OneMacOStoRuleThemAll, they'll finally lock down the bootloader on all Macs (why do you want to install anything else other an Apple OS?) and force all software install only through the App Store.

    • R1D3R 3 hours ago ago

      Apple software updates are always a downgrade. It's an opportunity to abuse customers that Apple just can't resist. If you're lucky all they do is break your muscle memory by moving buttons pointlessly.

      • thewileyone a minute ago ago

        Gave up on Apple after my MBP is effectively stuck in High Sierra and can't run anything modern, no thanks to the App Store removing older versions of software.

    • drooopy 4 hours ago ago

      Among other signs of awfulness, macOS 27 (and 26 before it) half the battery life of my M1 Air, forcing me to stay on Sequoia for a 2nd year.

    • icedchai 2 hours ago ago

      26 felt like more of a disaster than 27! I waited about 8 months to upgrade to 26, and upgraded to 27 right away.

    • otterley 4 hours ago ago

      What does that mean?

      • sys_64738 4 hours ago ago

        Maybe referring to the Apple Superintelligence being auto-added to macOS 27.

        • varispeed 4 hours ago ago

          I'll wait for Apple Supremeintelligence in macOS 29

  • varispeed 4 hours ago ago

    I upgraded and this system is a dumpster fire. Lags, random crashes, performance issues, random CPU spikes...

  • throwaway27448 4 hours ago ago

    For those of you who have never heard of this, it's macos's LVM. Why they didn't just refer to it as LVM is beyond me.

    • duskwuff 4 hours ago ago

      > Why they didn't just refer to it as LVM is beyond me.

      Because it isn't LVM, and giving it the same name as another similar-but-distinct technology would just make matters more confusing.

      • Grombobulous 4 hours ago ago

        According to the Wikipedia article about CoreStorage, it seems like the primary/only use case was Fusion drives (hybrid SSD/HDD hardware).

        The article says “It renders your expensive storage hardware completely useless.” but I’m really curious what that hardware could actually be. This seems like a pretty dead technology.

        • kstrauser 4 hours ago ago

          I've gotta agree. I'm not sure what expensive storage hardware would be both relevant today and unable to migrate off CoreStorage. For example, my most expensive storage is a NAS with an iSCSI target, and it couldn't care less what blocks I write to it. If I had a CoreStorage setup on it, I could migrate the data to a new target and then reuse that space for something else. The hardware wouldn't mind, or even know, that I'd changed what's on it.

          You mentioned old, obsolete Fusion drives. I'm having a hard time thinking of anything else where that'd matter, so you're probably right about that. AFAIK you can reformat those to use something other than CoreStorage if you're actually stuck using those boat anchors.

        • MilaM 3 hours ago ago

          CoreStorage was also used for HFS+ formatted and encrypted external storage like Time Machine backups. If you have any of those in your archive you might not be able to read them in the future.

        • mikepurvis 4 hours ago ago

          Sidebar, but as an end user, I remain annoyed that there isn't seemingly something that's a worthy successor to fusion drives.

          Like I have an Unraid box with dual NVMe (RAID1) as the "cache" drive and a bunch of spinning disks as the "array", but it's also very manual, like torrents get downloaded first to cache and then a nightly job syncs them to the array. Feels like a real missed opportunity to not be able to have this kind of config transparently managed.

          • Grombobulous 3 hours ago ago

            The successor is SSDs, and I think for what Apple was using fusion drives for they are worthy successors.

            The 2.5” form factor also took up a ton of space in a laptop form factor.

            With my NAS box (TrueNAS ZFS) I don’t bother with a cache. I struggle to justify the cost/benefit ratio. The sustained write speed of a 3.5” disk isn’t so bad for the most common NAS use cases.

            If I could go back to 2024 I think I’d use a m.2 2280 array for my NAS just because my present tense brain would think it was cheap. I don’t even hoard that much content so 4-8TB would be fine.

            Maybe one of these nifty things would be fun: https://www.bee-link.com/products/beelink-me-mini-n150

          • hypercube33 an hour ago ago

            Windows storage spaces can do this as well. It's been pulled from the non server line for 11 years or something.

          • jmgao 3 hours ago ago

            bcachefs with foreground_target/background_target/promote_target set appropriately does this automagically: https://bcachefs.org/Caching/

        • hagbard_c 3 hours ago ago

          I have one of those in an ageing late 2009 27" iMac running Linux. It is a Seagate ST2000DX001-1CM1, a 2TB "SSHD" which comes down to having 8 GB of NAND storage bolted on to a conventional 2TB drive. It doesn't need any special driver to do its thing so I wonder what that CoreStorage bit is supposed to be about.

          • wtallis 3 hours ago ago

            Did you install that SSHD as an aftermarket upgrade? I thought the Fusion Drive configurations shipped by Apple used normal hard drives and separate SSDs and were purely software-managed (and also used much more than 8GB of flash).

          • mrpippy 3 hours ago ago

            Apple sold iMacs for many years that had a completely separate SSD and HDD, and CoreStorage was used to combine them into a single block device which was then partitioned and formatted as HFS+ or APFS.

      • throwaway27448 4 hours ago ago

        Does it not manage logical volumes?

      • sysguest 4 hours ago ago

        ...like route 53? which is "dns configuration, but fancier"

        • zamadatix 4 hours ago ago

          AFAIK "Route 53" was a net new name for such a product?

    • vondur 4 hours ago ago

      It doesn't really do everything that a real LVM does though. This was used to support those annoyingly bad Fusion Drives. They dropped them around 2020 I think.

      • throwaway27448 4 hours ago ago

        > It doesn't really do everything that a real LVM does though.

        It manages logical volumes. Any quibbling is a matter of degree.

  • whatever1 3 hours ago ago

    Why do people try to force macOS things that it does not like to do? macOS does not like not apple hardware, period.

    For backups use a NAS. You can find from completely plug and play options to bring your own machine ones.