Mac App Store: "An unknown error occurred (100)" when purchasing

When attempting to purchase an app, an alert might appear indicating the app couldn't be purchased, as well as "An unknown error occurred (100)".

Try the following steps to workaround this issue:

  1. Quit App Store.
  2. Wait 10 seconds or more.
  3. Open App Store again.
  4. Navigate to the desired app.
  5. Click Buy.

If the issue persists, try restarting your computer and attempting the app purchase again.

Learn more

  • For other solutions to App Store issues, see Troubleshooting the Mac App Store.
  • You can find additional information by choosing Help > App Store Help from within the application.
  • Additional articles and support resources for Mac App Store are available from the Apple Support Website.
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