Seeing a Command Prompt box flash quickly on Windows 10? It's because of Office, and here's the fix.

If you recently started noticing a Command Prompt box flashing quickly every hour on your Windows 10 computer, you should know that it's not a virus or malware trying to steal your information. It's actually a bug with Microsoft Office 365.

The anomaly is caused by two tasks, including OfficeBackgroundTaskHandlerRegistration and OfficeBackgroundTaskHandlerLogon that Office 365 automatically configures with the Task Scheduler on Task Scheduler Library > Microsoft > Office. And every time they run, they cause a window to appear quickly in the screen every hour, and every time you sign in to Windows 10. However, this is not an issue affecting everyone; it only seems to be happening for those users who are enrolled in the Fast ring of the Office Insider Program.

There is a workaround floating around the internet, but the fact is that Microsoft is aware of the bug, and it has already fixed the problem. However, the fix is included starting with build 16.0.8201.2025, which currently is only available for those who are participating in the Slow ring of the Office Insider Program.

How to stop the Command Prompt box flashing quickly

The update will eventually roll out to everyone, but if this Command Prompt box flashing quickly on the screen every hour keeps bothering you, it's possible to temporarily enroll your installation of Office 365 to the Slow ring using the following steps to address the issue:

  1. Open an Office 2016 application.
  2. Click on File.
  3. Click on Account
  4. Click the Office Insider tile.
  5. Click on Join Office Insider.

  1. Check the Sign me up for early access to new releases of Office option.
  2. Select the Insider Slow level.

  1. Click OK to complete the enrollment.

Once you completed the steps, check for update and your Office 365 installation should now install the latest version available in the Slow ring, which includes the fix.

More Windows 10 resources

For more help articles, coverage, and answers to common questions about Windows 10 visit the following resources:

Mauro Huculak

Mauro Huculak is technical writer for His primary focus is to write comprehensive how-tos to help users get the most out of Windows 10 and its many related technologies. He has an IT background with professional certifications from Microsoft, Cisco, and CompTIA, and he's a recognized member of the Microsoft MVP community.