TFS 2015 RTM - Build vNext Failing with No Logs

Hi All,

I've recently set up a brand new server with a brand new install of TFS 2015 RTM.  I've done all of the defaults on the install.

I'm trying to "migrate" from the old XAML builds to the new build system.  I have one build step which is an MSBuild step.

For some reason, whenever I queue a new build, the build starts to run and then fails.  When I download the build logs, I have a ZIP file with a BUILD folder in it and nothing else.  No logs or anything.

Am I missing something?  Does MSBuild need more than just my solution file?

Thanks!