The issue seems to be related to a Microsoft Office task that runs in the background. Microsoft has been aware of the issue and a fix is available, but only if you’re in the Windows Insider program on the Slow ring, MS Power User reports.
The issue was first identified in the Microsoft Answers forum on April 14 and the culprit is the “OfficeBackgroundHandlerRegistration” task. It can be found running in the Task Manager on any machine with the production version of Office installed, and Microsoft issued a fix in Office 2016 build 16.0.8201.2025.
That is the version you will be running if you are an Office Insider Slow ring user and are updated to the latest preview version available in that ring. If not, then you will need to take a few steps if you want to stop the command prompt from flashing every hour or so.
First, open the Task Scheduler app as an administrator. The easiest method is to go to the Cortana search field and enter “Task Scheduler,” then right-click on the app and select “Run as administrator.”
Next, expand the Task Scheduler Library, and then Microsoft, and select Office.
Right-click on “OfficeBackgroundTaskHandlerRegistration” and select “Disable.”
That is all you need to do. Once the task is disabled, the command prompt will no longer pop up unexpectedly. There does not seem to be any negative effect from disabling the task, and so it is a reasonable step to take until Microsoft pushes a fix to all version of Office. Of course, you could always go here and sign up for the Office Insider program and put your machine on the Slow ring, with the added benefit of getting early access to some new Office features.
