Apple: here’s how to fix an issue with Security Update 2017-001 on the Mac

Apple has released a support document to help you deal with the issue. 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:

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