Controlling File Permissions in Shared Folders
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.
Over at StackExchange, a contributor came up with a long command-line invocation you can use in Terminal to set a folder to keep permissions set correctly, but it only works when files are created in the folder—if you move a file or multiple items in, they don’t inherit the right permissions. If you’re comfortable with the Terminal, this will certainly reduce the problem but not get rid of it.
Apple does offer a $20 upgrade for macOS that lets you turn a Mac into a more full-featured server, including better controls for folder access.
This is one of the other things that Dropbox made easy.
