I believe the way to resolve this is to set up ACL inheritance permissions on the parent folder. More about this here.

Firstly enable ACL permissions for SMB shares with the following command.

sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.smb.server AclsEnabled -bool YES

Then set up inheritance permissions on the parent holder with the following command. This should recursively go through your share and apply the relevant permissions.

sudo chmod -R +a "group:REPLACE_WITH_YOURGROUP_NAME:allow readattr,writeattr,readextattr,writeextattr,readsecurity,list,search,add_file,add_subdirectory,delete_child,file_inherit,directory_inherit" REPLACE_WITH_PATH_TO_PARENT_SHARED_FOLDER

To be safe I'd recommend creating a test share to try the chmod command before applying it to your company's share. Then once you are sure you get the right results apply it to the live/production share.

Answer from Alistair McMillan on Stack Exchange
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Apple Support
support.apple.com › guide › mac-help › set-up-file-sharing-on-mac-mh17131 › mac
Set up file sharing on Mac - Apple Support
Turn on File Sharing. If you want all users to have full access to the disk on your Mac, turn on “Allow full disk access for all users.” · To select a specific folder to share, click at the bottom of the Shared Folders list, locate the folder, select it, then click Open.
Discussions

macos - How to automatically apply permissions to files added to a shared folder - Ask Different
Nobody else in the same group could even read the file who were scanned by the group member. ... Find the answer to your question by asking. Ask question ... See similar questions with these tags. ... 1 How can I prohibit network users from accessing other user's home folders using Server permissions? ... 2 Permissions issue with shared folder using SMB. macOS ... More on apple.stackexchange.com
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Issues with File Sharing permissions. Looking for clues.
What OS are you running on that MacMini? How are you managing the permissions....from within Sys Prefs > File Sharing? Sounds like ACLs need to be adjusted accordingly so the folders/files inherit permissions properly. Go here and read the 2nd post down from Strontium90 which covers the details: https://discussions.apple.com/thread/254305733?sortBy=best Here is a quick blurb from that post: It is possible but you must use Terminal to add the file_inherit and directory_inherit attributes to the ACL on the parent folder. A quick explanation. There are two types of permissions on macOS; POSIX and ACLs. POSIX permissions do not deliver inheritance. ACLs do, as long as you properly create the ACL. So you need to adjust the ACLs so they inherit permission properly. More on reddit.com
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February 5, 2024
macos - OSX - File Sharing - Permission problems - Ask Different
I bought a Mac Mini (OSX High Sierra), also with the intention to use it as a file server. I am very surprised that this seems to be an issue. I am using Samba share that is also supposed to work ... More on apple.stackexchange.com
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October 25, 2018
How to force specific permissions on a shared folder on macOS | MacRumors Forums
Here's my story: I have a Brother ... named "brother" in macOS (Ventura) and setup everything in the web interface of the printer and indeed, the scans appear in the shared folder. However, the file created by the printer only gets u+rw permissions:... More on forums.macrumors.com
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February 23, 2023
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MacPaw
macpaw.com › how to › tips & tricks › guides
Mac file sharing is not working? Here are 4 tips to try
August 12, 2025 - To set permissions for a shared folder, select it in the ‘Shared Folders’ panel in the File Sharing pane of System Settings, then click your username in the right panel and click the arrows to choose permissions.
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iDownloadBlog
idownloadblog.com › home › how to manage permissions for files and folders on mac
How to manage permissions for files and folders on Mac
November 19, 2025 - Learn how to manage file and folder permissions on Mac and allow read only, write only, editing access, as well as no access at all. If you share your Mac with others and don’t set up separate user accounts or allow others to connect via file sharing, you may have some items that you want to protect.
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Macinstruct
macinstruct.com › tutorials › how-to-set-file-permissions-on-a-mac
How to Set File Permissions on a Mac | Macinstruct
The Info window allows you to modify permissions for users, groups, and everyone else. It doesn’t provide the same level of granular control as the chmod command, which you’ll learn about in the next section, but it’s a good way to quickly limit access to a file or folder.
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Macworld
macworld.com › home › how-to
Why read/write permissions go awry with macOS File Sharing | Macworld
April 24, 2017 - Apple adds extended file attributes on top of this that can be used by apps or the system. But despite all the control over who can do what, there’s shockingly no way to lock permissions for a given folder such that everything created in it, modified in it, or added to it inherits the permissions of the parent folder. That is, you’d expect you could say, “Shared Folder should always be reachable for everyone who has access to this system,” and yet there’s no simple way to ensure that.
Find elsewhere
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MacPaw
macpaw.com › how to › privacy & security › data privacy
How to change permissions on Mac to keep your data private
January 14, 2025 - Users can view file permissions using the Finder info window. In Finder, right-click the file or folder and choose Get Info from the menu or press Command + I to open this window. Click the Sharing & Permissions triangle to see the item permissions.
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Reddit
reddit.com › r/macsysadmin › issues with file sharing permissions. looking for clues.
r/macsysadmin on Reddit: Issues with File Sharing permissions. Looking for clues.
February 5, 2024 -

Hi all,

Not exactly sure if this is the right place to ask this question so if it's incorrect, please point me in the right direction.

At work, we use a Mac mini, connected to a Pegasus raid array to store files for regular use. We're a design agency with multiple users and everyone needs to be able to create, edit and move files around the server share freely. Previously, this hasn't been an issue. We recently lost our Mac mini through hardware failure and have had to replace it. Setup seemed to go well, our users were able to access everything easily.

After 2 days of operation, we discovered that the user-level permissions were a little out of whack. If a user created a file or folder on the server share, like normal, the permissions would be Read & Write for them, and Read-Only for all other users. Manually changing the folder settings was easy enough, but cumbersome and time consuming. Network devices, such as scanners which were previously able to save documents to the server, were creating files that has no permissions at all. Administrator level accounts had to open and resave the file, the manually change the permissions. This creates a huge amount of unnecessary file handling and work should a user forget to manually change the permissions of a file or folder.

The previous system administrator must have figured a work around or changed some settings, but did not leave notes and no solutions have been recorded. We've attempted changing individual umask settings, but that appears to have no effect. Today we attempted to edit the launchd-user.conf and change the default permission settings of new files and folders, again it didn't appear to have any effect. In the end, we completely reinstalled MacOS to see if it was an installation or system error. It wasn't, the issue remains.

Any ideas? I'm really pulling my hair out over this one.

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MacStadium
macstadium.com › blog › understanding-file-permissions-on-mac
Understanding File Permissions on Mac
October 7, 2021 - There are permissions granted to the single user who owns the file, the group of users the owner is associated with, and everyone else. ... User: The owner of a given file – the file’s creator by default.
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Johnhendron
johnhendron.net › 2022 › 04 › 06 › macos-permissions-after-file-sharing
MacOS Permissions After File Sharing – John Hendron
April 6, 2022 - The user on the Monterrey machine does not have administrator access. What surprised me was that adding additional share points via the Sharing panel would result in changes to the file permissions. Looking at individual files (such as the Chrome preferences) had essentially locked every file ...
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MacRumors
forums.macrumors.com › macs › networking
How to force specific permissions on a shared folder on macOS | MacRumors Forums
February 23, 2023 - All you have to do is highlight the shared folder, do a command button push+I and do get Info on the folder and change it's permission from there really easily! ... ACLs in user home folders are tricky, especially because they are invisble to ...
Top answer
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39

You can't do this with traditional POSIX-style permissions, but you can with inheritable access control entries. To allow read+write access for the entire "staff" group to everything in /Users/Shared/reallyshared, you'd use:

sudo chmod -R +a "staff allow list,add_file,search,add_subdirectory,delete_child,readattr,writeattr,readextattr,writeextattr,readsecurity,file_inherit,directory_inherit" /Users/Shared/reallyshared

The file_inherit,directory_inherit part means that this access control entry will automatically be added to new files & folders created inside this folder, but it doesn't automatically apply to items already there (that's why I added the -R flag to chmod -- that applies it to everything currently within the folder), and it won't be applied to items created somewhere else and then moved into this folder (I don't know of a way around this, sorry).

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Another approach is to use Terminal (a.k.a shell or command prompt) to create/edit (must be performed as super-user, see sudo) the file:
/etc/launchd-user.conf
adding the line:
umask 000
save and reboot. New files/folders (including files changed by save as) will allow everyone read/write.

This works by changing the default file creation permissions for programs, whereas the ACL approach works in terms of access rules bound to particular files and folders.

Without this tweak, files are created allowing user: read-write, group & other: read-only.

If you are sharing between multiple computers, you need to do this for all computers that will use the share.

If you have existing files and folder in the shared area, you need to make them all readable/writable by everyone using:
sudo chmod -R og+w <shared-folder-name>

The command reads in English as change mode, recursive through all sub folders and files, other & group permissions add write access, starting at folder with .

This approach is mentioned in forums to work with at least as early as 10.6 and still works on 10.7.

Other factors still affect access to content. For example, permissions set in the Sharing control panel, home folder permissions/ACLs, and when using Terminal any umask in effect for the shell.

Look up umask and Posix file permissions for details on these Unix concepts. In the write ups, the word directory is Unix parlance synonymous with folder. You will also encounter the terms UID and GID: user and group IDs, which define the Posix ownership of running programs (processes). Note that UIDs and GIDs are numbers which may be the same or different for a given user name across different computers. These numbers are assigned to names in the order accounts are created on a given computer, typically starting with ID 501. Home networks lack a mechanism to harmonize these assignments across computers. Therefore on network shares a file may appear to belong to different users because the user ID to user name binding is determined from the perspective of computer is accessing the file. So shares really always allows everyone to access files to various degrees of everyone. In other words, the Posix "other" permission is an indefinite limit on access ranging from allowing a quite predictable but apparently uncertain degree of access depending on the user IDs assigned on different computers. This leads to apparently absurd variations in experiences, where on some networks, for example a setup with only one user account ever created on each Mac, will be able to share without any permissions tweaks because all accounts will have the same UID (501, no matter what the accounts are named) whereas another network using multiple user accounts per Mac will see problems right away. So some groups will never struggle with this, whereas some others may see problems that develop over time, or problems which appear/disappear spontaneously, depending on when/how additional user accounts are created/used with the shared folder.

It's a mystery why Apple has left such a festering usability defect in the configuration of such an otherwise easy to enable file sharing capability.

On external disks, this problem is addressed with the "Ignore permissions on this volume" option. There may be a similar feature for apple file sharing, but where is it.

If you roll you own Samba service config there are other mechanisms for handling these problems, but Samba is not at all easy to use.

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Apple Community
discussions.apple.com › thread › 7566517
set permissions and privileges for new fi… - Apple Community
September 13, 2016 - Here is how you configure this, without any SIP privilege changes. On your computer, in System Preferences : Sharing, you check File Sharing. Initially, it will be off (red dot), and under options, you can select one or both of SMB and AFP sharing. For Shared folders, you click the + symbol ...
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Macworld
macworld.com › home › how-to
How to use file sharing on your Mac | Macworld
May 19, 2022 - The permissions next to each user or group entry are the same as found in the Finder: Read & Write: All access, including deleting items and adding them. Read Only: Retrieve anything in the folder, including nested items.
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Davidson Technology & Innovation
support.ti.davidson.edu › hc › en-us › articles › 360020943854-Create-a-shared-folder-on-a-Mac-computer
Create a shared folder on a Mac computer – Davidson Technology & Innovation
In the Apple drop-down menu, select System Preferences... On the System Preferences dialog box, on the third row of applets, click on the Sharing icon. ... In the Service pane, click on the File Sharing check box.
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Apple Community
discussions.apple.com › thread › 254095462
All sharing settings (users and folders a… - Apple Community
I've hit on this above. However, here is the expanded view. The three permissions are r w and x and there are three blocks that can be granted rights; the owner, the group, and other. Now, where does 755 come from? ... By using this math, any combination of these items will result in a unique sum.
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Macworld
macworld.com › home › software › how-to
Exploring the Mac's sharing features | Macworld
February 22, 2013 - At the bottom of the Info window that remains open, click the triangle that appears next to Sharing & Permissions. You’ll see three listings: your username, ‘Staff’, and ‘Everyone’. Next to your user name will be the words ‘Read & Write’. ‘Read only’ appears next to ‘Staff’ ...