Fixing the “Failed to Enable Personal Hotspot” Error
Some of my older Macs running High Sierra or Mojave were unable to join the Personal Hotspot of one or even two of my iPhones.
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There is a file called com.apple.airport.preferences.plist in the folder /Library/Preferences/SystemConfiguration.
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Delete this file. But that will also reset all your network interfaces[…]
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If you’re more adept, edit the file, e.g. with the app PrefEdit or BBEdit, then find all entries that mention “phone”, and remove those. After saving the changes, you should be able to reconnect to the phone without even requiring a restart.
