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
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.