UE4 Keeps Freezing


I’m having a big problem with UE4. It keeps freezing, I can’t kill the process so I had to restart my computer. The issue happens usually after Build finishes. Build finishes fine I have everything responsive on UE4 but as soon as click the viewport it hangs and never comes back. But it’s not limited to Build, it sometimes happens if I click save all, or select something in menu or have a sip of tea… When it hangs it’s just UE4, everything else works fine. v4.24.3 and v4.25.0 has the same behaviour, but v.4.24.3 is crashes more often.

I’m trying to learn UE4 but my experience so far is horrible. I don’t have overclocking or overheating. Max CPU temp I’m seeing is 70C (2h OCCT/small dataset run).

PC Specs:

AMD Ryzen 9 3950x

So far:

  • Reinstalled Win10
  • Reinstalled UE4
  • Verified Win10 with sfc /scannow
  • Verified UE4
  • OCCT test cpu 2h - passed
  • Furmark test gpu 2h - passed
  • Memtest ram overnight - passed

Can anyone please guide me? It feels like my UE4 journey will end without even finishing. I have to reboot every 10 mins.

Please let me know if there are any logs I can check.


This happen to me when i use folliange editing, seems it use 1 uv for light map when you build and it just freeze, that for me atleast, i just add every object manualy so i wont get any errors, that might be problem, now just keep in mind im not an expert, this is how my editor freeze, you didnt give any explination on what you did before you press build or save.


Thank you for the replies. I’m just a beginner so all I have done is a big green field with some bumps like little hills on it. I click save or I click build then once it’s finished building or saving UE4 stops responding. I don’t need to change, add or remove anything. I can do 3 builds in a row and it will definitely stop responding. Or I can save few times and it will stop responding. I don’t think it’s related to what I’m doing to be honest, I’m not capable of doing anything yet. And with these issues I don’t think I’ll ever be able to do anything anyway.


Hello again,

I was suspecting that my motherboard might be faulty. I just got it replaced by a new one, tested for a week with prime95 and furmark. Hardware looks stable. Fresh Win10, wiped all drives installed from scratch.

And yet again UE4 survives only few minutes. I had log windows up on one of my screens this time and right before the slow down/freeze I’ve seen the following messages:

During these messages flooding the output log UE4 slowed down extremely and finally became totaly irresponsive. Since I’m working on a specific thing and doing it exactly the same way everytime - I think either I’m reproducing a bug or the heightmap I’m using causing some issues. I have google’d the error message but I can’t find any documents that helps.

Does anyone have any opinions?