After you migrated to Microsoft 365 Exchange, if the following error message appears when you open Outlook, please follow the steps below to update the Registry key.

  1. Close Outlook.
  2. Right-click here, select Save Link As..., and save the file to your desktop.


  3. Double-click the SignInOption0.reg on your desktop


  4. Click Run.


  5. Click Yes to User Account Control prompt.

  6. Click Yes.


  7. Click OK.


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