How to discover which files should be readable and which writable: PermissionScanner 1.0b1

Repairing permissions on your Home folder is a blunt tool, which could set incorrect permissions and other settings on some files. At the same time, it could fix problems with Preference settings files without them having to be trashed.

In the first instance, it might be more useful to have a tool which scans appropriate folders of your choice, and checks whether you, as a user, can read or write to the files inside them. If one of your Preference files has become unmodifiable, you will then be able to identify it, and correct whatever is wrong with its permissions, rather than trashing it and starting again.

This is a classic scripting problem, so I offer a modern scripting solution in PermissionScanner, a simple app written in Swift for Sierra which does exactly that. The latest release is available from Downloads above.


PermissionScanner gives you a choice of scanning the two folders which contain traditional Preference files, ~/Library/Preferences or /Library/Preferences, together with the Library folder in your Home folder, or the whole Home folder. You can choose whether to list all those files which are not writable by you as a user, or those which are not even readable.

The two most useful scans appear to be:

  • of ~/Library/Preferences (‘Home Preferences’) for files which are not writable; this is very quick, and should not return any filenames, although there are usually one or two exceptions.
  • of /Library/Preferences for files which are not readable; this is very quick, and should not return more than a couple of filenames, which are again the oddities in the folder.

You can broaden the scan out to cover the whole of your Home folder if you wish. That will take a long time, minutes perhaps, cover more than a million files in many cases, and may return thousands of potential problems.

When you have identified files which look as if they might have incorrect permissions, you can then change their permissions manually, rather than using the long and potentially troubling process of repairing permissions on the whole of your Home folder.

This first beta appears stable, and does not write to any of those important folders. I am particularly interested in developing this tool to highlight potential problems with permissions which users can address quickly and simply. All feedback is very welcome, please.