I have Ryzen 9 5900x 16Gb RAM RTX 3070ti and cannot get any version of 5 to run I keep getting the lost GPU message at sstartup. I have tried reinstalling, running from SSD, updated drivers, patching the registry, but nothing works. Even dropping to DX11 does not help and I realy want to use Nanite. It appears this has been a problem for many people for the past few years but there is no conclusive answer to the issue.
Hi @jimbobaggins ,
This problem is quite common and documented in
Reducing GPU Timeout Detection and Recovery Crashes
There is lots of useful information for EPIC GPU Lightmass which uses direct X 12 DXR shaders.
Currently the latest version 5.4 preview works with this.
UEFN 26.10 5.4 automatically switches allegedly this on 
Hello
Thanks for the response but the problem isn’t with a scene it is when just starting the editor without any scene. I also tried the suggestion as indicated in the article you linked to actually increasing the time out to 120 seconds and it still did not work. All of the 5 versions get to the firsst sscreen where you choose a file to load and then crash having lost the GPU.
Okay so just for the record I could not get any version of 5 to run with the new RTX3070ti although I had been able to get 5.0.3 to run previously with a RTX 2070. Anyway upon running 5.0.3 the crash gave me a message about D:/Build being in accessible which is not the drive I have the engine installed on. So I decided to try starting the engine from within it’s folder using Start as Administraor and it worked and I could load a scene in which I had previously compiled the shaders. So then I exited and tried to start it again from the folder with Administrator it worked and so I chose a scene in which I had not compiled the shaders and it crashed.