Several people, including myself, have found that the following fonts cause the Display Unit to fail:
AirbusPFD.ttf
AirbusPFD2.ttf
CDU.ttf (which apparently is a Captain Sim-installed font)
CDU_WXR.TTF
In my case, I copied the fonts to another folder for safe keeping, then I deleted the fonts.
Once done, I was able to start up the DU without any issues. Adding them back in, and the problem returns.
I have the Windows 10 UPGRADE OS.
There may be other fonts that also lead to the problem...