Should you try repairing permissions in High Sierra or later?

Just over a year ago, Sierra users got a bit of a surprise. After years of repairing permissions as a panacea, with the arrival of SIP that had been withdrawn. Yet suddenly Apple was recommending that we returned to repairing permissions, albeit on our Home folders.

Apple’s original article has since been slightly updated, but its advice remains the same: there’s a long list of problems for which repairing permissions on your Home folder can be curative.

This advice was published just as Sierra got its last update, to macOS 10.12.6. That autumn, Apple unleashed High Sierra 10.13 on us, and repairing permissions was driven to the back of the mind as we wrestled with its succession of major problems, and shortcomings in APFS.

With High Sierra in what is probably its last incarnation, and Mojave moving closer every day, I thought it was about time to review the process of repairing permissions on your Home folder, and whether it’s something that you should consider doing in High Sierra and beyond.

A success?

User experiences of the results of doing this are surprisingly good. My original articles of last year remain among the most popular on this site, and there are many comments from those who have enjoyed miraculous cures as a result of this treatment. A few have not, but I can’t recall seeing any comment that repairing permissions made anything worse.

Apple’s article might, though, make us more cautious: read its banner closely once again
Resolve issues caused by changing the permissions of items in your home folder
If you change the read or write permissions of items in your home folder, you might need to reset permissions to avoid certain issues.

Note that this is directed at users who have changed the permissions of items in their Home folder. That’s not something that many of us do very often. However, if the procedure is good, sound and safe to use when we have changed permissions, surely it should also be sound and safe to use even if the permissions are correct?

Is it available?

One of my other concerns at the time was that, although recommended in this article, the command in question
diskutil resetUserPermissions
was not documented in diskutil‘s man page, nor anywhere else unless you happen to type in those two words. Because of the parlous state of Apple’s documentation, there are now many commands and options which are used daily but have not yet made it into man pages. That isn’t a good indicator of whether they are good, sound or safe to use.

What is more important is whether resetUserPermissions is even available in High Sierra or later. Try typing the command into Terminal, and you’ll see that, though this solution may still be in hiding, it looks permanent for the time being.

What to do?

Apple’s suggested process remains unchanged too: start by setting the Home folder permissions to Read & Write using the Get Info dialog, and propagate that throughout your Home folder. If that doesn’t fix your problems (which is normally the case), use the command
diskutil resetUserPermissions / `id -u`
in Terminal to finish the job off. If that returns an error -69841, you should type into Terminal
chflags -R nouchg ~
then repeat the diskutil command.

Not so simple now

There are some modern issues which could confound this solution.

If you run my PermissionScanner app over a modern Home folder, you’ll see that many files and folders in the Home folder are normally not even readable by an admin user. Typically these include some folders inside Photos libraries, and a great deal in ~/Library/Containers, where app sandboxes are kept.

There are also potential issues with putting your Desktop & Documents folders in iCloud. As these are part of your Home folder in a way that iCloud Drive normally isn’t, permissions often stray from those which you might expect. I’m not sure that I would want to meddle with those permissions, and I hope that diskutil is wise enough to avoid doing so too.

Should you consider using it?

My conclusion is, therefore, that if your Mac is suffering from any of the symptoms which Apple says could result from incorrect Home folder permissions, repairing Home folder permissions using the sequence recommended by Apple could fix them in Sierra, High Sierra, and later. Those symptoms include:

  • Changed System Preferences or the Dock doesn’t stick;
  • Prompts for an admin password when moving items in your Home folder;
  • Repeated messages that macOS needs to repair your Library to run applications;
  • Trying to save files results in warnings that the file is locked, or you don’t have permission;
  • Sandboxed apps quit unexpectedly when you open them;
  • Alerts that your startup disk has no more space available for application memory;
  • Safari or SafariDAVClient are using large amounts of system resources in Activity Monitor;
  • General performance is impaired;
  • iTunes reports that an iOS device cannot be synced;
  • When you import photos or video into Photos (or iPhoto), they don’t appear in the app, but appear in Finder instead;
  • Photos libraries need to be updated or reselected each time you open Photos.

I’d be very interested to hear of your experiences repairing Home folder permissions in High Sierra and later, please.