Security Update 2017-001 for High Sierra Breaks File Sharing for Some Users »

Today’s fix for Apple’s nasty root account bug has broken file sharing for some users, including on my iMac. Apple has published a fix, and I assume this will be resolved in a future, less critical software update:

  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.