If you’re getting the dreaded “compiler limit: internal heap limit reached” and the corresponding “Failed to create virtual memory for PCH” then you can use the /ZmXXXX switch to increase the heap memory allocated to precompiled header (PCH) compilation.
Luckily, it’s very easy to do in UE4, just put this
…in your target.cs:
WindowsPlatform.PCHMemoryAllocationFactor = 2000;
…or in your BuildConfiguration.xml:
If you’re putting it in the BuildConfiguration.xml then it will apply to any and all of your UE4 projects and will trigger a recompile of source-built engines!
You can increase this number further, it is not a MegaByte figure, rather a scale. More info here: