8

Could someone tell what is the Preboot folder in /Volumes and may I delete it?

$ ls -l /Volumes/
total 0
0 lrwxr-xr-x  1 root  wheel   1 Oct 20 12:13 Macintosh HD -> /
0 drwxr-xr-x+ 3 root  wheel  96 Sep 26 11:25 Preboot

UPD: Here is the files list inside Preboot folder.

  • Another buggy construct. I have two... lrwxr-xr-x 1 root wheel 1 Dec 23 10:43 C -> / drwxr-xr-x+ 3 root wheel 96 Sep 16 08:11 Preboot drwxr-xr-x+ 3 root wheel 96 Oct 7 15:59 Preboot 1 drwx--x--x+ 3 root wheel 96 Dec 23 09:49 com.apple.TimeMachine.localsnapshots – William Cerniuk Dec 23 '17 at 16:32
8

The Preboot volume is a new system partition that manages boot, the partition is created during the update to macOS High Sierra to support booting to an APFS volume(The one named Macintosh HD).
APFS is a new filesystem created by Apple, and it makes a lot of changes(link to Wikipedia article about APFS), and one of them is the addition of the Preboot volume, which is required to boot APFS, so if you delete it, you can't boot!

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  • Are you sure your other Mac uses APFS?, Macs with fusion drives doesn't use/support APFS, at the moment... – Harcker Oct 21 '17 at 19:56
  • Yes. I'm sure. I'm already checked two Macs about this folder. – SimWhite Oct 22 '17 at 4:26
  • I didn't have any Preboot partition because I upgraded to High Sierra as opposed to installing it from scratch. Then High sierra refused to encrypt my disk (enable FileVault) until I had a Preboot partition. The only way I found I could create a Preboot partition is by re-installing from scratch from createinstallmedia – MarcH Nov 14 '18 at 17:00
  • All you write is likely correct about the Preboot volume. But at least here, /Volumes/Preboot is a folder that is not related to the volume — mount does not show that volume (here /dev/disk1s2) mounted there. Moreover, if I mount the volume by hand, the contents of the volume are not identical to the contents of the folder, tho those folders might be outdated copies. – Blaisorblade Oct 24 '19 at 7:14
2

I made backup and delete this folder. Everything is working fine. So I think this folder is a part of update process of something like this.

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  • 1
    Hi, may I ask you, do you have your disk encrypted? I found some info that Preboot folder might be related and needed when you have your disk encrypted. Thanks for reply. – Tomas Sykora Nov 30 '17 at 1:41
  • Yes. It was encrypted from the beginning. So it's not related. – SimWhite Nov 30 '17 at 4:54
0

If you find one or more "Preboot" folder at the root of your disk after upgrading to macOS Catalina (10.15), you can hide them with the following method:

  1. Disable SIP (you'll have to boot into the Recovery system for that), e.g. see https://support.studionetworksolutions.com/hc/en-us/articles/115003839246-How-to-disable-Systems-Integrity-Protection-SIP-in-macOS

  2. Once back in normal Catalina, go into Terminal and enter: "sudo mount -uw /". This makes the system volume writable (which is read-only by default since Catalina).

  3. Now hide the Preboot folder with these Terminal commands (only one is needed but I don't know which - if you figured it out, leave a comment and I'll update this answer):

sudo chflags hidden /Volumes/Preboot*
sudo chflags hidden /Preboot*
  1. Now you can enable SIP again.
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