Build From Source Deploys Files To Wrong Location

I got a source build of UE4 going, but have had a problem with it deploying files to an incorrect location. The Source installation is on my D:\ drive, but files always seem to get written to a subdirectory on C:\VTRoot (the path typically matches the correct location other than the C:\VTRoot bit). If I copy the files that get put there back to the correct location, everything works, but that is rather inconvenient as it does this whenever I need to generate visual studio files on my project.

Is there a way to redirect this automatically? A setting for UnrealHeaderTool or something?

If it helps, I also have a (non-source) 4.18 installation from the UE4 Launcher, also on my D:\ drive, and that works without issue.

Figured it out, it was Comodo Firewall.

Solution was to unblock UnrealHeaderTool.exe and UE4Editor.exe. Temporarily disabling auto-containment while compiling may also be of benefit as there seem to be a lot of temporary command files that are executed.