Clicking "Build" Hard Crashes engine.

Here’s the callstack.

Access violation - code c0000005 (first/second chance not available)

UE4Editor_D3D11RHI + 402205 bytes
UE4Editor_RHI + 237528 bytes
UE4Editor_ShaderCore + 191019 bytes
UE4Editor_Renderer + 1556139 bytes
UE4Editor_Renderer + 2487418 bytes
UE4Editor_Renderer + 2094968 bytes
UE4Editor_Renderer + 2103363 bytes
UE4Editor_Renderer + 2402336 bytes
UE4Editor_Renderer + 2397830 bytes
UE4Editor_Renderer + 2418804 bytes
UE4Editor_Renderer + 1447574 bytes
UE4Editor_Renderer + 682649 bytes
UE4Editor_Renderer + 1174897 bytes
UE4Editor_Renderer + 1174144 bytes
UE4Editor_Renderer + 1606005 bytes
UE4Editor_Engine + 8029663 bytes
UE4Editor_UnrealEd + 10114132 bytes
UE4Editor_UnrealEd + 10140495 bytes
UE4Editor_UnrealEd + 9992657 bytes
UE4Editor_UnrealEd + 10495562 bytes
UE4Editor_UnrealEd + 10305293 bytes
UE4Editor_UnrealEd + 10342208 bytes
UE4Editor_UnrealEd + 10305966 bytes
UE4Editor_UnrealEd + 2121567 bytes
UE4Editor_LevelEditor + 570935 bytes
UE4Editor_Slate + 588774 bytes
UE4Editor_Slate + 1535133 bytes
UE4Editor_Slate + 1030727 bytes
UE4Editor_Slate + 1037049 bytes
UE4Editor_Slate + 1435577 bytes
UE4Editor_Slate + 2116506 bytes
UE4Editor_Slate + 2296435 bytes
UE4Editor_Slate + 432060 bytes
UE4Editor_Slate + 160583 bytes
UE4Editor_Slate + 832224 bytes
UE4Editor_Slate + 770598 bytes
UE4Editor_Core + 2484713 bytes
UE4Editor_Core + 2400763 bytes
UE4Editor_Core + 2489275 bytes
UE4Editor_Core + 2387186 bytes
user32 + 9268 bytes
user32 + 8855 bytes
UE4Editor_Core + 2490486 bytes
UE4Editor!FEngineLoop::Tick() + 3434 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\launchengineloop.cpp:2193]
UE4Editor!GuardedMain() + 479 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\launch.cpp:131]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

Anyone have any idea what’s causing this.

FYI I’ve tried a number of potential fixes, including drivers and clearing folders.


Are you getting a crash reporter pop up when the engine crashes? If so can you please upload the Machine ID that this popup reproduces? Also are you experiencing this problem in all projects even sample projects or only a specific project.

Thank You



It’s happening only in my project, in a couple of levels. It seems to be linked to a skylight. when there is no skylight, everything builds fine, but if I put a new skylight in it will cause the same crash. I’ve done several tests, including putting at least one of every asset used in a clean blank scene and no crash. Without fail though, there will be a crash if I have a skylight in one of the crashing scenes.


From the logs I am seeing and your description, can you take a look at the projects and levels that are causing this issue and look at the lighting setup for any references to a sky light listed as NULL. These references could be in blueprints or in the level itself. If found, delete them and save all.

Also, do you have any scene render actors in BPs or in your level?

The other option to get you back up and building is to do a lighting wipe and delete all lights and reflection actors in your level and rebuild them.

Let me know -


SO, it was sorted out by clicking “Build Lighting Only” There’s something else going on beyond just lights, our team is looking into it. Thanks for the help though!