WinDiff

[kinook]

First, you don't need to run windiff under the command shell (C:\WINDOWS\system32\cmd.exe /C), but I wouldn't expect that to make a difference on the exitcode. Most likely, windiff is returning a non-zero exitcode for this call in both scenarios, and you're just not checking it when running from the command-line. You can either add value that as a success exitcode or mark the step to ignore failure if you don't want the build to stop.