A user at my company had an issue with Excel. On nearly every Excel document he opened, as he would scroll around, black and grey boxes would appear.

If he minimized Excel, the view would reset until he started scrolling again.

His set up is:

Surface Pro 4, 8 GB, with dual external monitors – so he has 3 displays total, and Windows 10 Enterprise. Monitors are set to Extended, and the Surface display was the primary monitor.

I noticed that his desktop looked odd, icons were chunky / pixelated, and there were things appearing where they should not be appearing, aka screen particles…

To fix the issue, I set the larger external monitor as the primary monitor, and signed out and signed back in. The desktop icons now look normal, and when I open any Excel document, there are no more black and grey boxes.

Since Windows 8 – it seems that is a display that uses scaling is the primary monitor, the other external displays do not look as good as they should.

I hope this helps others too!