PowerPoint is huge on a second monitor

If you are running Windows 10 and you have a high-DPI monitor such as in a Surface Pro 3, and connect to a second monitor using a Mini-DisplayPort adapter, then open PowerPoint, its very likely that you will find this:

PowerPoint DPI problems Surface Pro 3, Windows 10, Office 365

If you haven’t seem the problem personally, it might be difficult to guess from the picture what is going on. The problem is that PowerPoint’s Ribbon is huge given that it is running in a 21″ monitor and not in a tablet anymore.

The problem doesn’t seem to occur with Word or Excel when they are transposed from the Surface screen to the external monitor. It seems to be exclusively related to PowerPoint.

Hopefully, there is a solution for this problem. If you have Office 365, open the file

C:Program FilesMicrosoft Office 15rootoffice15powerpnt.exe.manifest

Using a text editor. Then, look for word True/PM in the following block:

And change it to:

Now save and open PowerPoint. PowerPoint should not auto-scale properly when you transpose its window from the Surface Pro 3 screen and to external monitor, and vice-versa:

PowerPoint Windows 10 Surface Pro 3 - normal DPI