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Question: Big Sur has an "OS Update" snapshot volume under the Big Sur volume. Do I need it?

I performed a clean install of Big Sur by creating a new volume called Big Sur within Catalina, and then installing Big Sur to it from a thumbdrive. It's been working great.


But now I have a volume under my Big Sur volume called com.apple.os.update-GUID. I don't recall seeing a volume like this in previous versions of macOS. Is this a new feature of Big Sur, or is this a leftover from how I installed Big Sur? If it's a leftover, is it safe to delete?

MacBook Pro 16″, macOS 11.0

Posted on Nov 18, 2020 5:58 AM

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Nov 18, 2020 6:54 AM in response to CincyTriGuy In response to CincyTriGuy

The Update volume is a normal part of Big Sur.

Apple used to stage updates in /Library/Updates folder, but it now appears they have started staging in an APFS Volume, instead. There still is an Updates folder in Library, so it may be related to something else, perhaps OS updates as opposed to other updates.


I have no way of knowing, but I don't think they intended to show that in Disk Utility.

Nov 18, 2020 6:54 AM

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Nov 18, 2020 6:54 AM in response to CincyTriGuy In response to CincyTriGuy

The Update volume is a normal part of Big Sur.

Apple used to stage updates in /Library/Updates folder, but it now appears they have started staging in an APFS Volume, instead. There still is an Updates folder in Library, so it may be related to something else, perhaps OS updates as opposed to other updates.


I have no way of knowing, but I don't think they intended to show that in Disk Utility.

Nov 18, 2020 6:54 AM

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Dec 25, 2020 7:04 PM in response to CincyTriGuy In response to CincyTriGuy

Here is an example. Please do not delete any volumes in the APFS Container.


/dev/disk0 (internal, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *500.3 GB   disk0

   1:                        EFI ⁨EFI⁩                     314.6 MB   disk0s1

   2:                 Apple_APFS ⁨Container disk1⁩         500.0 GB   disk0s2



/dev/disk1 (synthesized):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      APFS Container Scheme -                      +500.0 GB   disk1

                                 Physical Store disk0s2

   1:                APFS Volume ⁨Macintosh HD⁩            15.3 GB    disk1s1

   2:              APFS Snapshot ⁨com.apple.os.update-...⁩ 15.3 GB    disk1s1s1

   3:                APFS Volume ⁨Macintosh HD - Data⁩     252.4 GB   disk1s2

   4:                APFS Volume ⁨Preboot⁩                 474.0 MB   disk1s3

   5:                APFS Volume ⁨Recovery⁩                610.8 MB   disk1s4

   6:                APFS Volume ⁨VM⁩                      1.1 GB     disk1s5


If you need more details, see https://eclecticlight.co/2020/09/16/boot-volume-layout/ as reference.

Dec 25, 2020 7:04 PM

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Dec 28, 2020 12:15 PM in response to CincyTriGuy In response to CincyTriGuy

Hi,


I also have the same question, I was baffled once I saw that 10% of my available disk space is blocked by this snapshot. The problem is I cannot delete it in disk utility. Anyone has an idea how to delete this volume? Or will this be un-blocked automatically at some point?


Regards,

Robert

Dec 28, 2020 12:15 PM

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Jan 5, 2021 8:41 PM in response to CincyTriGuy In response to CincyTriGuy

Is this volume has something to do with the excessive and large "Others" file volume in Storage management view?


I was wondering why I have so much space taken from my SSD in my unused brand new M1 MBP when I suddenly jumped into disk utility and find out that there is a com.apple.os sharing the entire SSD volume with Macintosh HD.

Makes kinda sense a secured copy of the OS plus cache and apps temp files so far kinda makes up to the space taken by "other", since CleanMyMacX could exactly detect everything.

Jan 5, 2021 8:41 PM

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Jan 5, 2021 11:53 PM in response to CincyTriGuy In response to CincyTriGuy

When it comes time to install a major macOS update, Big Sur loads up a separate snapshot of your system volume in the same APFS container as your system and data volumes (this volume is a persistent hidden volume called “Update,”


https://arstechnica.com/gadgets/2020/11/macos-11-0-big-sur-the-ars-technica-review/11/#h3

Jan 5, 2021 11:53 PM

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Question: Big Sur has an "OS Update" snapshot volume under the Big Sur volume. Do I need it?