XPS 15 9550 Freeze randomly - Black screen

To give an update, Dell replaced my motherboard yesterday and it has been working find without any issue since. I will keep it on for the next few days to see if this is truly fixed. 

What's the  BIOS version comes with the new motherboard? and have you updated all drivers?

It comes with 1.0.5, the technician updated it to the latest (1.1.19). I didn't redo my system, so all the drivers are already up to date.

Same issue with my XPS 15 9550. Random grey screens requiring pushing power button to force shutdown. On the system history, appcrash, igfxext errors each time. Tried updating drivers/bios to no avail. Currently in contact by email with dell technician, trying usual steps--no progress thus far.

Also having the same issue, Nvidia is to blame for this for a less than reliable GPU..

I hope this can be fixed thru Bios update soon, otherwise having to change motherboard is too much work..

I disabled the 960m and haven't had issues since, but I bought this laptop specifically to use the 960m

Same problem. Random black screens. Only way out is to push the power button until the system shuts down. After disabling the Nvidia 960m in the Windows Device Manager no issues at all.

Is it an hardware problem or can it be fixed with a firmware/driver update?

Some on this post have their motherboard replaced - it seemed working for them.

I'm not in a rush sending my laptop in, but I've contacted dell, hope this problem can be solved by a BIOS update. 

hoping for a bios update fix for this.

Actually I've been disabling the 960m for 4 days now, and it still happens, just a lot less often !

Problem was gone for me with m960 disabled. Now I have a new motherboard and the m960 and all is fine for now. Upgraded BIOS to 1.1.19.

OK, so I now actually have my XPS 15-9550 running with the 960m enabled without any crashes.  NOTE! - this worked for me, can't guarantee it'll work for you.

-Go to Settings, Apps, and search for anything with the word "Nvidia" in it.  Uninstall all Nvidia drivers and programs.  You will likely have to reboot at least once and go back to Apps to get them all.

-Go to Settings, Device Manager, and right click on the 960m display adapter, and choose to "Remove Device" - make sure that "Delete Device Driver" is checked.

-Open File Explorer, go to "Program Files" and "Program Files (x86)".  Delete the "Nvidia Corporation" folders in both locations.  (See where I'm going with this?)

-Restart the computer.

-After the screen stops resizing and blinking after the reboot, go to Settings, "Device Manager" and verify that the 960m is back.  You'll now be running on the Microsoft drivers for the 960m which it turns out actually appear to work.  They might not be cutting edge with all the bells and whistles, but...

I'm going to play with it a bit more tonight to see if I can isolate exactly which part of the Nvidia package is causing the issue.  My initial guess based on some earlier work is that it's in the PhysX program/drivers/whatnot, but I won't be sure until I crash the machine again.

Hope this helps someone out there!  

If it were a driver issue, how do you explain that the issue is solved by replacing the motherboard while keeping the exact same Windows installation on my ssd with all the same drivers?

Never said that I think it's a driver issue.  All I said is "this is a workaround to at least bring it back online" and "I'm going to play with it some more."  I posted as a "hey, this at least does something to mitigate the issue" - if the post isn't useful, I'll happily remove it.  I have played with it some more since and it doesn't matter what version Nvidia driver you use, the problem persists, even if only the driver is installed.

I'm just peeved that I have to replace hardware in a brand new system.

Same here: replaced the laptop, put back my Samsung 950 Pro SSD with the exact same Windows installation and device drivers and the problem is gone.
In addition, with the old laptop, I'd experience the same freezes & blank screens even with the 960m disabled.

In my case it was definitively an hardware issue.

@chrispete  definitely not a fix to install older drivers. This might be either from bios or hardware replacement.