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Writing on Macintosh HD

crunge007

crunge007

macrumors newbie
Original poster
Apr 4, 2025
3
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Hi everyone, I'm supporting a friend who is currently abroad for work. He has received a new MacBook and is in the process of setting it up. For a specific program, it is necessary to store data directly on the hard drive (Macintosh HD), essentially next to the System folder. However, this is not possible due to missing permissions. We have disabled SIP and enabled the root user, but this had no effect. Does anyone know what needs to be done to make this work?
 
The Macintosh HD volume is read-only, you can't create a folder that will appear next to the System folder.
If you open Disk Utility, right-click on the Data Volume and select Show in Finder, you can create a folder in that location. It appears in Finder as Macintosh HD - System - Volumes - Macintosh HD and in Terminal as /System/Volumes/Data/.
From the program you could try to select that location as the destination for its data storage.
 
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From my own observations, one can no longer create a folder at the root level of the OS boot volume (by this, I mean what you see when you open "Macintosh HD" on the desktop).

You CAN create as many folders as you want inside your own user folder.

On my old Intel Mac Mini, I partitioned the internal SSD into 4 partitions:
Boot (APFS)
Main (HFS+)
Media (HFS+)
Music (HFS+)

When I got my new M4 Mini several weeks' back, I tried the same approach.
And... it worked.
I'm probably the only Mini user on planet Earth that has partitioned the m4 SSD into 4 partitions, again:
Boot (APFS)
Main (HFS+)
Media (HFS+)
Music (HFS+)

But.. it CAN be done, if that's what you want.
I'm old, I'm used to that setup, and I'll keep using it until...
 
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That means it no longer works like it used to, where you could just set full access or write permissions for Macintosh HD somewhere, right? Is there no trick to remove this restriction? Creating partitions is probably not an option.
 
OP wrote:
"Is there no trick to remove this restriction?"

My guess (and it's ONLY "a guess") is that there is not.
 
Also, this could just be unix permissions at play and nothing to do with Apple's SIP or anything else.

There isn't enough in the OPs posts to know.
 
smithrh said:
Also, this could just be unix permissions at play and nothing to do with Apple's SIP or anything else.

There isn't enough in the OPs posts to know.
Click to expand...
Can you create on your Mac a folder on Macintosh HD next to the System folder?
 
crunge007 said:
Hi everyone, I'm supporting a friend who is currently abroad for work. He has received a new MacBook and is in the process of setting it up. For a specific program, it is necessary to store data directly on the hard drive (Macintosh HD), essentially next to the System folder. However, this is not possible due to missing permissions. We have disabled SIP and enabled the root user, but this had no effect. Does anyone know what needs to be done to make this work?
Click to expand...
What is the use of this? If you create a special folder on /Users, IT IS ON THE SAME DISK.
Who cares on what exact spot of the volume.
Can you explain what the purpose is of your friend's intentions?
;JOOP!
 
crunge007 said:
However, this is not possible due to missing permissions. We have disabled SIP and enabled the root user, but this had no effect. Does anyone know what needs to be done to make this work?
Click to expand...
What needs to be done: You need to talk to the developer of the program (as @kitKAC says, what program?, what version?) about being able to have the folder somewhere else.
Why: Recent major versions of macOS do not allow anything/anybody to create folders in the root of the system/boot drive as it appears in Finder. The nearest you will get is as @bogdanw said in his first post. Whether that is sufficient for the specific program (what program?) we can't say.

Disabling SIP and enabling the root user reduces the security of the Mac. Probably not a serious issue (I have SIP partially disabled) but, depending on the friend's circumstances, you should undo those changes.
 
Last edited:
gilby101 said:
What needs to be done: You need to talk to the developer of the program (as @kitKAC says, what program?, what version?) about being able to have the folder somewhere else.
Why: Recent major versions of macOS do not allow anything/anybody to create folders in the root of the system/boot drive as it appears in Finder. The nearest you will get is as @bogdanw said in his first post. Whether that is sufficient for the specific program (what program?) we can't say.

Disabling SIP and enabling the root user reduces the security of the Mac. Probably not a serious issue (I have SIP partially disabled) but, depending on the friend's circumstances, you should undo those changes.
Click to expand...
As MacOS is based on UNIX, the locking of the system area's is one of the best improvements of the OS.
Microsoft Windows does the same in a flurry way, why it is much more vulnerable.
And about the program developer: over the years I have seen several commercial installations turn
to trash because of the lack of discipline of the application designers who ended up almost fighting
when their files showed up in the same wrong places.
;JOOP!
 
Unfortunately i only know as much as i said. 🙈 when this was possible with former versions of macOS, it must be possible now. I need someone with macOs developer knowledge 😜
 
smithrh said:
What does "next to" mean exactly?
Click to expand...
When you open Macintosh HD in Finder you see Applications, Library, System, Users and your folder.
When you run ls /Volumes/Macintosh\ HD in Terminal you see your folder as well.
 
crunge007 said:
Unfortunately i only know as much as i said. 🙈 when this was possible with former versions of macOS, it must be possible now. I need someone with macOs developer knowledge 😜
Click to expand...
You mean: you need someone who is willing to CHANGE APPLE policy.
Well, start with buying APPLE shares: those are cheap these days.
;JOOP!
 
crunge007 said:
For a specific program, it is necessary to store data directly on the hard drive (Macintosh HD), essentially next to the System folder. However, this is not possible due to missing permissions. We have disabled SIP and enabled the root user, but this had no effect. Does anyone know what needs to be done to make this work?
Click to expand...


It may be possible to create a user-defined symbolic link at the root level of the "merged" boot volume by creating an appropriate /etc/synthetic.conf file. Pretty interesting, but I have not tried this! If you do, please let us know the results!

Sequoia man synthetic.conf -- see especially the last two examples:
SYNTHETIC.CONF(5) File Formats Manual SYNTHETIC.CONF(5)

NAME
synthetic.conf – synthetic symbolic link and directory manifest

DESCRIPTION
synthetic.conf describes virtual symbolic links and empty directories to be created at the root mount
point. Because the root mount point is read-only as of macOS 10.15, physical files may not be created
at this location. All writeable paths must reside on the data volume, which is mounted at
/System/Volumes/Data.

synthetic.conf provides a mechanism for some limited, user-controlled file-creation at /. The
synthetic entities described in this file are synthesized by the kernel during early system boot.
They are not physically present on the disk, but when the system is booted, they behave as if they
were within certain parameters.

synthetic.conf is intended to be used for creating mount points at / (e.g. for use as NFS mount points
in enterprise deployments) and symbolic links (e.g. for creating a package manager root without
modifying the system volume). synthetic.conf is read by apfs.util(8) during early system boot.

FILES
/etc/synthetic.conf

CONFIGURATION DIRECTORY
Individual subsystems may add their own synthetic manifests to /etc/synthetic.d to avoid having to
append to the content of synthetic.conf. This is similar to the mechanisms which exist for shell and
manual page paths, paths.d and manpaths.d, respectively. If multiple manifests specify the same
synthetic link or directory name, the one respected by the implementation is undefined. The structure
of these manifests is identical to that of synthetic.conf.

FORMAT
synthetic.conf specifies a single synthetic entity per line. Each line may have one or two columns,
separated by a tab character. If a line has a single column, it denotes a virtual empty directory to
be created at /. If a line has two columns, it denotes a symbolic link at / whose link target is
given in the second column.

In either case, the first column denotes the name of the entity to be created at /.

A line beginning with the # character indicates a comment that is not parsed.

SYNTHETIC ENTITIES
Synthetic entities may not be deleted at runtime. In order to delete a synthetic entity, it must be
removed from synthetic.conf, and the host must be rebooted.

New files and directories may not be created within a synthetic empty directory.

EXAMPLES
# create an empty directory named "foo" at / which may be mounted over
foo

# create a symbolic link named "bar" at / which points to
# "System/Volumes/Data/bar", a writeable location at the root of the data volume
bar System/Volumes/Data/bar

# create a symbolic link named "baz" at / which points to "Users/me/baz"
baz Users/me/baz
Click to expand...
 
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Brian33 said:
It may be possible to create a user-defined symbolic link at the root level of the "merged" boot volume by creating an appropriate /etc/synthetic.conf file. Pretty interesting, but I have not tried this! If you do, please let us know the results!
Click to expand...
I tried it in a 15.4 virtual machine and it works. At first, it failed to boot after restart and the solution was to use Tab as a separator between baz and Users/me/baz.
https://derflounder.wordpress.com/2...ctories-and-symbolic-links-on-macos-catalina/
 
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