[SOLVED] How to "force the WiX .exes to run out-of-process"

How to "force the WiX .exes to run out-of-process"

There is a bug in the WiX plugin for Visual Studio where file locks on referenced DLLs are not properly released. Therefore, you have to restart Visual Studio every time you want to recompile a custom extension DLL or any assembly referenced by it.

This is a known bug, but the issue was closed because there seems to be a solution / workaround:

You can force the WiX .exes to run out-of-process to avoid the lock MSBuild has.

I don't understand how to achieve this. I checked...

the properties of my WiX setup project
the properties of the extension assembly (C# class library)
all Visual Studio settings
the available command line arguments of candle.exe

...but did not find anything. What am I missing? How do I apply this workaround?

I'm using WiX 3.10 and Visual Studio 2013.

Solution

The example that I've seen several times around the web is to add <RunWixToolsOutOfProc>true</RunWixToolsOutOfProc> to the Wix Installer's project file within a property group. Unfortunately, documentation of this feature has thus far eluded me.