Here is a tip if you are having issues with Microsoft 365 Apps when trying to login to activate Office (error 1200).

  • Update to the latest Microsoft Apps version
  • Delete content in these folders:
    • C:\Users\user\AppData\Local\Microsoft\IdentityCache
    • C:\Users\user\AppData\Local\Microsoft\OneAuth
    • C:\Users\user\AppData\Local\Packages\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy
  • Run powershell as user (non admin)
    • Add-AppxPackage -Register “$env:windir\SystemApps\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\Appxmanifest.xml” -DisableDevelopmentMode -ForceApplicationShutdown
    • Add-AppxPackage -Register “$env:windir\SystemApps\Microsoft.Windows.CloudExperienceHost_cw5n1h2txyewy\Appxmanifest.xml” -DisableDevelopmentMode -ForceApplicationShutdown
  • Delete Subkeys under
    • HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities
  • Reboot and try logging in to Microsoft Apps

References:

https://www.borncity.com/blog/2023/10/30/office-365-neues-zum-anmeldefehler-1001-sign-in-error-1001-microsoft-verffentlicht-workaround/