After upgrading to 4.26.1 and opening a project, the screen goes black (Not the window, the entire screen)
(Even waited up to an hour at one point).
Tried creating a new project and had the same result, haven’t found a fix yet
Older engines before 4.26 wont let me port a newer version of a project
Is there anyway to downgrade back to 4.26.0, otherwise cant use my project
I have problem too. My project just crash on start, I need downgrade or fix, but I dont know how.
This is the error on log:
LoginId:e80d69024d87ab5e3974f394d90378de
EpicAccountId:f5153b16302e4f43b7c4348fe2a8d933
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000060
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll
Similar problem here : 4.26 worked fine, after updating to 4.26.1 the engine is launched OK, but opening any project or creating a new one ends up with an empty desktop. The editor isn’t visible, and only restarting windows quits the app. 4.25.4 not affected and still works fine.
I can’t read C++ and have no idea how to approach this…
It’s worth noting that this is a few years old laptop, and on my newer desktop, which has better graphics hardware, the update went smooth and everything works as expected.
Best of luck 
4.26.1 is crashing. How can I roll back to 4.26?
Try upgrading to 4.26.3 first.
I have the same issue too, after upgrade to 4.26.2, my Landscape material and other material are missing a material function.
4.26.3 Isn’t out yet? I have a similar issue with my landscape materials, and particles are invisible. How can I downgrade to 4.26?
The same issue happened to me after upgrading to 4.26.1, after 10 minutes of work the entire engine starts blinking black color randomly, also when I right click somewhere in the project.
My project was exactly the same. Still has weird flickering lighting issues sometimes but I just disabled all the displacement maps on the landscape textures and that helped. Next time I won’t update mid-project I guess.
1:install new ue4.26.2
2:create new empty project, Migrate your map to new project and set gamemode/copy old config ini