Launching the problem was compiling the projects locally just fine, but the TFS assembly reports that the assemblies could not be found.
The log file will display:
2> C: \ Program Files (X86) \ MSBuild \ 12.0 \ Bin \ amd64 \ Microsoft.Common.CurrentVersion.targets (1696.5): warning MSB3245: Failed to resolve this link. Could not find assembly "HtmlAgilityPack". Make sure the assembly exists on disk. If this link is required by your code, you may get a collection of errors. [C: \ Builds \ 1 \ MYPROJ \ MYPROJ-Dev Site \ SRC \ MYPROJ \ MyProj.Domain \ MyProj.Domain.csproj] For SearchPath "{HintPathFromItem}". It is considered ".. \ packages \ HtmlAgilityPack.1.4.6 \ lib \ Net45 \ HtmlAgilityPack.dll", but it was not.
The problem is that there is a specific folder / packages / in the directory:
C: \ Builds \ 1 \ MYPROJ \ MYPROJ-Dev Site \ SRC \ MYPROJ \ packages \
Is the relative hint path any other way on the TFS server? It looks like this would be relative to the .csproj file that he was viewing. I can confirm in the build output folder that the package (and the DLL) exactly where HintPath points should be.
Update: I found a solution to my problem. This is double. Firstly, I cannot read the file explorer and did not notice that in my HtmlAgilityPack folder there is only an XML package file and not the actual DLL. Secondly, I had to remove the packages folder from TFS by going to Source Control Explorer and deleting it from my project. TFS handled the rest. Now everything is building correctly.
: http://robertgreiner.com/2013/09/team-foundation-service-build-error-nuget/