Preboot folders

Did you do a clean install or upgrade?

Clean, with partial migration.

Well I guess it‘s time for a clean install. 😩

Because you're seeing some extra folders in your root directory??

10.15.1 didn't fix it for me...

Have you also tried my solution (https://discussions.apple.com/thread/250715308?answerId=251449074022#251449074022)? Didn't it work? Would've been less of a hassle than re-installing macOS.

I looked at it but didn't want to deal with SIP or mess around with terminal commands. The reinstall only took an hour or so and was painless.

I had some very weird folders and issues when I updated from Mojave to Catalina.

Decided to erase the disk and go for a fresh install instead - works well and I now don't have bizarre issues like duplicate Macintosh HD - Data volumes and non-hidden system folders all over the place

Thanks for the help. I tried your FindAnyFile app, however when I tried to make the Preboot folder invisible, the app crashed. I sent the crash report to you. I suspect that Apple has locked down these folders and there simply is no way to alter them which is frustrating...

The crash is a known bug in FAF v2.0 that occurs when trying to hide or unhide a file fails (I'll get that fixed soon) - that's how I learned about this Preboot folder issue. Did you run FAF's search in root mode, though? That's important (it's equivalent to using the "sudo" command in Terminal).

How did you look for the Preboot folder? You have to look into the TWO volumes you should see, such as "Macintosh HD" and "Macintosh HD Data", and you probably won't see them in Finder but only find them with FAF or by listing them in Terminal.

Try this: Boot your Mojave or older system. Then open Terminal.app (in /Applications/Utilities) and paste the following line into its window, then typing the Return key:

for vol in /Volumes/*; do ls -lad $vol/Pre* 2>/dev/null; done

That should list any Preboot folders on any of your local volumes. If you get any output, paste that here, and we'll see from there.

Thomas Tempelmann wrote:

How did you look for the Preboot folder? You have to look into the TWO volumes you should see, such as "Macintosh HD" and "Macintosh HD Data"

I used FAF in root mode on both volumes (labeled Catalina and Catalina - Data in my setup) per your recommendation.

Try this: Boot your Mojave or older system. Then open Terminal.app (in /Applications/Utilities) and paste the following line into its window, then typing the Return key:

for vol in /Volumes/*; do ls -lad $vol/Pre* 2>/dev/null; done

That should list any Preboot folders on any of your local volumes. If you get any output, paste that here, and we'll see from there.

% for vol in /Volumes/*; do ls -lad $vol/Pre* 2>/dev/null; done
zsh: no matches found: /Volumes/Catalina/Pre*
zsh: no matches found: /Volumes/Catalina - Data/Pre*
zsh: no matches found: /Volumes/Glyph 3TB-1/Pre*
zsh: no matches found: /Volumes/Glyph 3TB-2/Pre*
zsh: no matches found: /Volumes/Macintosh SSD/Pre*
zsh: no matches found: /Volumes/com.apple.TimeMachine.localsnapshots/Pre*

Oh, that's not working as I thought, then. There is indeed no hidden Preboot folder in any of your volumes' root dirs.

(BTW, I assume it's you who named it "Mactintosh SSD"? I suspect Apple still calls the initial volume "Mactintosh HD", even when it's an SSD, right?)

There's still the possibility that the Preboot folder you're seeing is actually the same-named volume in the same APFS partition, or perhaps even in a _different_ partition (and Catalina confusing them). But then it should usually appear as a volume, not as a folder in your root dir.

Please enter "diskutil list" in Terminal and show us the output here. It'll list one or more volumes named "Preboot". Feel free to shorten the list, removing disks that have no Preboot elements. If you have at least as many Preboot volumes on all your disks as you see in Catalina's root folder, it would support my theory that those volumes are what you're seeing.

Next we'd try to mount these volumes and set them to be hidden explictly. As follows.

In Terminal (try this first in your pre-Catalina system, and if that doesn't work, try it in Catalina as well):

diskutil mount diskXsY

In place of diskXsY, use one of the disk... names that are shown as IDENTIFIER for one of your Preboot volumes from the earlier diskutil list.

The Preboot volume will probably not appear as a volume in Finder (but if it does, that would be great).

Now explicitly hide it:

sudo chflags hidden /Volumes/Preboot

You'll have to enter your Mac password.

Now reboot into Catalina. Does that remove one of your Preboot folders? That'd be great. If not, I'm out of ideas.

I did as you suggested and got the following output:

drwxr-xr-x  3 root  wheel  96 Oct 12  2017 /Volumes/System/Preboot

d--x--x--x  3 root  wheel  96 Oct 12  2017 /Volumes/System/Preboot 1

d--x--x--x  3 root  wheel  96 Oct 12  2017 /Volumes/System/Preboot 2

Alright! Now we're getting somewhere, finally.

Now that you see the Preboot names inside the /Volumes dir, try to use this command in Terminal:

sudo chflags hidden /Volumes/System/Preboot*

Let's hope that works.