macOS 27 does not support CoreStorage volumes

(wadetregaskis.com)

79 points | by colejohnson66 4 hours ago

8 comments

  • someonehere 11 minutes 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 minutes 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.
  • Marsymars 1 hour 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 7 minutes 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.

    • mrpippy 1 hour 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 48 minutes 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 39 minutes 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 40 minutes ago
          are you sure that is because of apfs? hdds are usually much slower, no?
    • isityettime 35 minutes ago
      Can you use OpenZFS?

      https://www.openzfsonosx.org/

  • hmartin 2 hours ago
    Also dropped support for FireWire drives, as I just found out the hard way.
    • traceroute66 1 hour 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 48 minutes 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.
    • reaperducer 21 minutes 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 1 hour ago
      did you go from 25 to 27?
  • exabrial 2 hours ago
    MacOs 27 is a disaster. All of the sudden, I have 35% of a computer left to do any kind of work.
    • thisislife2 1 hour 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 1 hour 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.
    • icedchai 17 minutes 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.
    • drooopy 2 hours 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.
      • Grombobulous 2 hours ago
        Couldn’t possibly have anything to do with a 6 year old battery I’m sure.
        • zbentley 1 hour ago
          Not GP, but: I had replaced the battery on my M1 Max 6mo ago with an aftermarket part. On MacOS 26 that routinely gave about 5 hours of coding/browsing/active screen time (no audio or massive CPU load other than unit test runs).

          Anecdotally, after updating to MacOS 27 2mo ago that time has been reduced by between a third and a half, doing the same kind of daily work on the exact same project, without major new apps installed or new always-open browser tabs.

          I don’t know if it’s the OS’s fault directly or the fault of an app I use that interacts poorly with the new OS’s power management, but either one is damning. I’m not doing anything particularly weird.

        • drooopy 1 hour ago
          I've replaced the battery earlier this year. With Sequoia I get about 14 hours of use (browsing with firefox, emails with thunderbird, youtube, spotify, apple pages and numbers). Last year when I "downgraded" to tahoe, my battery life was effectively halfed and returned to normal when I upgraded back to Sequoia. Same thing is true with GG this year.
    • otterley 2 hours ago
      What does that mean?
      • sys_64738 1 hour ago
        Maybe referring to the Apple Superintelligence being auto-added to macOS 27.
        • varispeed 1 hour ago
          I'll wait for Apple Supremeintelligence in macOS 29
  • varispeed 1 hour ago
    I upgraded and this system is a dumpster fire. Lags, random crashes, performance issues, random CPU spikes...
  • jon128 2 hours ago
    [flagged]
    • GrifMD 2 hours ago
      Darling, no one is going to take your grievances seriously when you speak like that.
  • throwaway27448 2 hours 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 2 hours 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 2 hours 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 1 hour 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 45 minutes 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 1 hour 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 56 minutes 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

          • jmgao 1 hour ago
            bcachefs with foreground_target/background_target/promote_target set appropriately does this automagically: https://bcachefs.org/Caching/
        • hagbard_c 1 hour 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 1 hour 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 1 hour 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 1 hour ago
        Does it not manage logical volumes?
      • sysguest 1 hour ago
        ...like route 53? which is "dns configuration, but fancier"
        • zamadatix 1 hour ago
          AFAIK "Route 53" was a net new name for such a product?
    • vondur 1 hour 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 1 hour 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 48 minutes 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.