WiX undefined preprocessor variable

Not sure how many people will see my small blog, but here I go, maybe it helps someone.

I recently had this WiX undefined preprocessor variable issue.

The actual variable was the same old $(var.MyProject.TargetDir)

After looking through the whole internet and not finding anything, the fix was a simple one.

The "MyProject" HAS TO BE EXACTLY THE SAME NAME as the web project that I added as a reference to the Wix project.
So if your project is called WhatewerWebAll, then you have to have something like:


You can say what you want, but the "undefined preprocessor variable $(var.MyProject.TargetDir)" message is actually not really describing the real issue, but maybe that's just me.

Wix heat command exited with code 319 (-out parameter must specify a file path)

• The '-out' or '-o' parameter must specify a file path. File: heat.exe
• The command " "C:\Program Files (x86)\WiX Toolset v3.7\bin\heat.exe" project "..\Web \" -gg -g1 -cg PACKAGEFILES sreg -dr DEPLOYFOLDER -out "C:\Users(...)\Server\Wix\Frags.wxs" " exited with code 319. File: C:\Users(...)\Server\Wix\Wix.wixproj

This was really not a lot of information for me to use.
What I fount out, is that Wix is throwing this error on anything. I will explain.

So this was my code:

"$(WIX)bin\heat.exe" dir "$(vm4heat)" -cg vm4heat -gg -scom -sreg -sfrag -srd -out "$(ProjectDir)\FilesFragment.wxs"

And as you can see, I have 3 different paths in my code.

The error message says that the issue is on the "out".

Well, the actual error was on the "dir".

So in case you ever get this error, don't look for wrong doing in the "out" parameter only. Check EVERY path, one by one. In my case it was an extra backslash at the end of the "dir" parameter.

Hope this helps.