UnrealBuildTool Crashes Computer When Building HTML5

So I recompiled the source code with modifications made to enable HTML5 project building, cooking, and packaging. During the process the UnrealBuildTool starts the Emscripten process which starts the conversion of the project to run in HTML5. During this time it creates dozens of Python and Node processes each using a decent portion of my systems resources. When I set these processes to Low priority and set their affinity to only use 1 of my 8 cores, they seem to ignore those settings and still continue to run at a process level of High and use all 8 of my cores. They each also using anywhere from 500mb to 1GB of RAM. Because of this the host computer is forced to instantly shutdown. I’m not sure what more I can do to try and prevent this, if anyone has any ideas/suggestions as to what do to to fix this I would love to hear them. On a 32 core machine, this issue is also present, but the machine does not shutdown as it continues to have a few cores not being maxed out to 100% usage.

I realize the HTML5 building options were not enabled by default for a reason, as it is not yet finished but it would be nice if there was a way to build HTML5 projects without the need of a 32 core system. If anymore information is needed I’ll be happy to provide it, I don’t think my system specs would be needed for a problem like this but I’ll post them anyways.

OS: Windows 7 64-bit SP1
CPU: AMF FX 8350 Black Edition (clocked currently at 4Ghz)
RAM: 16GB 2133 Mhz RAM
CPU: AMD HD 7770 Ghz Edition
Mobo: Asus M5A99FX Pro R2.0

You should post this on the AnswerHub.

This is a very interesting topic and I would appreciate to learn when and how is the process of publishing to Html5 will be available by default.
I think guys said in the last podcast that it was likely to appear in 4.1?

Please keep us updated on this as I and I am sure many others are interested in ability to pubilsh to HTML5


We just published documentation for our HTML5 platform support. You can view it here:

I tested this pipeline on my consumer-grade desktop PC (Core i5 3750K) and didn’t find the compile times overly long. Emscripten is a bit of a resource hog, but I usually just relinquish my machine to it during the build process.

Changing the priority on compiler threads can sometimes have unintended consequences. A safer solution would be to edit the ‘HTML5ToolChain.cs’ file and lower the numeric value in the following line:

Environment.SetEnvironmentVariable(“EMCC_CORES”, “8”);

You’ll then need to build UnrealFrontend and re-launch it.

Hope this helps!