Create a BuildConfiguration.xml file…
https://docs.unrealengine.com/en-US/…ion/index.html
…with something like this:
[FONT=Courier New]<?xml version="1.0" encoding="utf-8" ?>
<Configuration xmlns="https://www.unrealengine.com/BuildConfiguration">
<BuildConfiguration>
</BuildConfiguration>
<LocalExecutor>
<MaxProcessorCount>12</MaxProcessorCount>
</LocalExecutor>
<ParallelExecutor>
<MaxProcessorCount>12</MaxProcessorCount>
</ParallelExecutor>
</Configuration>