Problem
When the user right clicks on a Build within the 'Builds' menu of the Team Explorer in Visual Studio 2015, and clicks 'Edit Build Definition' they are taken to the Build Definition editor. Within the 'Process' tab, a Process Editor is opened that reads a XAML file and provides the configurable parameters. However, when attempting to add a new Build Definition, the user will receive a number of errors.
If the user clicks the 'New' button within the Process Editor, a prompt shows like so. If the correct Team Project location is selected, and a path is selected, then the user will receive a prompt reading "[The file you selected was not within a Git repository]."
If a manual entry of the 'Path in repository' textarea is attempted, the user will receive the error "[Object reference not set to an instance of an object.]"
Software
I am receiving this problem with VS 2015 14.0.25424.00 Update 3 and TFS Server 2013 12.0.30324.0 (Tfs2013.Update2)
Workaround
At the moment, there does not seem to be a fix. I believe that this may be a bug in Visual Studio 2015, but I'm not quite sure. The only information that I have found is that there could be a workaround by using a different version of Visual Studio.
Frequency
From my research, this seems to be an issue that people are encountering fairly often. There is a Social MSDN thread here that you may see the same issues, and the frequency at which it occurs.