I have upgraded to Wix 3.7, downloaded 3.7.4766.21408 of the extended bootstrapper and copied WixBalExtensionExt.dll to the bin folder. 

When attempting to add a reference in Visual Studio I get and error that it could not be added make sure it is accessible and a valid wix reference. 

One of my code monkey colleagues seems to think I have a missing dependency, have I missed a step out? 

Yours, one very confused tester 
Martin 

Can you confirm that you have WiX version 3.7 installed? Also, which version of Visual Studio are you using?

Windows Installer Xml Linker version 3.7.1224.0

Visual Studio 2010 version 10.0.40219.1 SP1 REL

I have just created a new project and added the reference and it worked ok, could you try it with a new project?

There is an incompatibility between WixBalExtensionExt.dll and the standard one so you shouldn't have both loaded but that only shows up when you try to build the code.

If you get the error with a clean project can you let me know the full details for the message.

I have just tried with a new project and got the same error, which is as follows.

"A reference to C:\Program Files(x86)\WIX Toolset v3.7\bin\WiXBalExtensionExt.dll could not be added.  Please make sure that the file is accessible, and that it is a valid WiX reference."

I copied the provided WiXBalExtensionExt.dll to C:\Program Files(x86)\WIX Toolset v3.7\bin, is there anything else needed?

And just to be sure I have installed WiX3.7 onto another machine running the same version of VS and I get the same error when trying to add the reference.

It looks like the file on Codeplex is corrupt, I'll do a new release.

The file wasn't corrupt I forgot that you need to unblock the file (the contents of all zip files you download are blocked by default on Windows 7). You won't be able to do this in "Program Files" so copy the file WiXBalExtensionExt.dll to the desktop, right click and select properties, click unblock and OK. Then copy the file back to "Program Files". 

Success, thanks very much.