Second Display Blurry

To resolve this issue, best to close and save everything you have open before you do the following next. Please sign out of windows (Crtl-Alt-Del) "Sign Out" and when you sign back in with the monitor connected, this should have now fixed this to correct the pixel scale view. If not please check if the external monitor is a different resolution/scale view then the laptop main screen? 

You can check this by right-clicking anywhere on the desktop and select "Display Settings" select the monitor number you wish to check and you will then see the settings. You can change them to try match and what works for you with the resolution or scale view.