Hi,
I understand that you would like to adjust scaling in Windows virtual machine, fonts size in Windows.
This issue occurred if some Windows applications are not adapted for HiDPi resolutions
First of all let me say that all Windows applications are not designed for Retina displays as Microsoft does not support it at all. With Parallels Desktop it is possible but please consider that this is only our customization through virtual drivers.
So the issue is not with Parallels Desktop, it is how Windows shows an application on the virtualized PC desktop.
The most optimal settings to get proper views re:
1) Mac's system preferences -> Displays. In resolution you need to change it from "Best for Retina" to Scaled (one item left from Best of Retina
2) Parallels Virtual Machine Configuration ( http://kb.parallels.com/en/117287 ) -> Hardware -> Video -> More space or Un-tick Retina support.
3) Set scaling as 100% (default) in Guest OS: - Go to Start menu > Control Panel > Display - Set size of text and icons size as 100% (default) 2. Restart Windows virtual machine.
After these setting everything should look fine.
For more information please refer this article http://kb.parallels.com/en/119926
Last edited: Jun 19, 2015