I\'m using VisualStudio Ultimate 2012 (Update 1) on Windows 7.
I can get my T4 template to generate a file by:
right click [tt file] | run Custom tool. That works g
I had this problem recently in my build process (not using DTE).
I resolved it by making sure I only had 1 texttransform.exe on my PC.
For some reason, the IDE was using a recent version of texttransform.exe and the msbuild an older one.