The item is already under source control at selected location

On my case, I had to correct the binding using the Change Source Control dialog box :

• Select solution or project that you want to add to source control
• Go to "File" -> "Source Control" -> "Advanced" -> "Change source control" (if you look at Microsoft website, you will see that there is not "Advanced" menu in their example, it may be related to VS version or menu settings).
• Click "Bind" on each row.
• If a row in underlined in red, it may indicate that the current project is not checked in into TFS, check-in all project before you proceed to the binding.

Microsoft - How to : Bind and Unbind Projects and Solutions

Close the solution . open the solution file in notepad Then remove the below section.

GlobalSection(TeamFoundationVersionControl) = preSolution
        SccNumberOfProjects = 2
        SccEnterpriseProvider = {3CF58AB4-18FA-4F8D-95D4-32DDF27D189R}
        SccTeamFoundationServer = https://serverIP/Project
        SccLocalPath0 = .
        SccProjectUniqueName1 = Ecample\\Example.csproj
        SccProjectName1 = Example
        SccLocalPath1 = Example
EndGlobalSection

then open the solution once again it should prompt to bind, do the binding properly.