I have an XPS 15 Notebook and have recently upgraded to Windows 8.1. Ever since the upgrade anything I plug into the mini display port doesnt work. I have tried my second monitor and projector both don't work. I have also tried different converters and the same result. I upgraded to the latest Nvidia and Intel drivers (the ones on the Dell support page are a bit dated) and no change. However I did notice that the moment I uninstall the Nvidia drivers the output works but the colors look a little scrambled. I was wondering if anyone else has had this issue and knows of a way to fix it.
I managed to solve the problem on my Alienware 14.
It has both Intel Integrated HD Graphics 4600 and NVidia 2Gb Geforce GTX 765M.
After the upgrade to 8.1, my 4600 is no longer detectable and my minidisplay port suddenly goes bonkers. So I thought I had to upgrade the Nvidia to recognize the port. All upgrades doesn't work and create havoc on my laptop.
What I did later was nothing short of luck. I kept downgrading the driver to 188.8.131.528
It worked like magic. So my laptop can now see all 3 monitors (one being the laptop screen). I hope this helps.
Oh by the way, you may need to upgrade your bios. I upgraded my bios which renders all the intel drivers updated in the intel download center excluding the 4600 integrated card.
Have you by any chance figured it out yet? I recently updated my XPS L501X to Windows 8.1 and my mini displayport also stopped working.
You'd be really helping me out here.