macOS High Sierra Security Fix Breaks File Sharing for Some Users – Here’s How To Fix It

Posted in Apple News, macOS on 30/11/2017 by Chris Hauk


Apple was quick to supply a fix for the macOS High Sierra security hole that allowed anyone to log into the Mac’s “root” System Administrator account without requiring a password. However, that fix caused some users to see file sharing fail to authenticate across multiple Macs. Apple has a fix.

macOS High Sierra Security Fix Breaks File Sharing for Some Users - Here's How To Fix It

In a support document, Apple instructs users how to fix the file sharing issue:

If file sharing doesn’t work after you install Security Update 2017-001, follow these steps.

If you experience issues with authenticating or connecting to file shares on your Mac after you install Security Update 2017-001 for macOS High Sierra 10.13.1, follow these steps to repair file sharing:

  1. Open the Terminal app, which is in the Utilities folder of your Applications folder.
  2. Type sudo /usr/libexec/configureLocalKDC and press Return.
  3. Enter your administrator password and press Return.
  4. Quit the Terminal app.

It isn’t known how many people are affected by the file sharing bug, but the issue appears to be caused by a system library error.

Apple quickly released a fix for the macOS High Sierra security flaw that allowed anyone to enable the root superuser on a Mac using a blank password. The bug, discovered by developer Lemi Ergin, allows anyone to log into an administrator account by using “root” as the username and a blank password.

The bug allows access to an administrator’s account on an unlocked Mac, and also allows access at the login screen of a locked Mac.

Apple promised a fix soon after news of the security hole hit media outlets on Tuesday. The company delivered the patch early Wednesday as Security Update 2017-001. The security patch is available through the “Update” tab in the Mac App Store.


Chris Hauk

MacTrast Senior Editor, and self-described "magnificent bastard," Chris Hauk owns Phoenix Rising Services and writes for everyone's favorite "bad movie" website, Big Bad Drive-In.

His first Apple product was an iPod Classic 9 years ago, and he has since added a MacBook Pro, a number of iPads, iPhones, and multiple Apple TVs to his collection.

He lives somewhere in the deep Southern part of America. Yes, he has to pump in both sunshine and the Internet.