Hey there @NeoGameFactory! Can I have a bit of a description of the situation?
Were you in editor and just working on something then it crashed or is this happening every time you launch?
Are you successfully able to open other (empty) projects?
May I see your specs?
Does it only occur in fullscreen?
By replying here I’m going to assume you’d already tried the TDRdelay fix and I know you swapped down to DX11 there, so we won’t retread those waters.
Some other solutions:
If you’re using Nvidia, swap from Game-Ready drivers to Studio Drivers.
If you have MSI afterburner or any other adjacent device that touches GPU side data it’s best disabled in Unreal’s case.
This thread has a bunch of possible solutions: Does anybody know how to fix d3d device being lost? - #9 by jwatte