Mysterious Error Message When Opening Version Controlled .NET Solution

Whenever I open the solution containing projects that are version controlled using TFS, I get the following error message:

"The Team Foundation Server[Server URL] is currently unavailable. Thie solution will be opened offline."

Now, as the message says, the Server is not available, but the funny thing is, I have removed the server information from the TFS server list, therefore this message should not occur under the current circumstances.

Why is this happening?

You may have removed the server from Team Explorer/TFS settings, but have you removed the source control bindings?

Open the solution, go to File -> Source Control -> Change Source Control...

Highlight all rows within the grid, and choose Unbind.

There'll still be a reference somewhere in the solution file, or quite possibly the project files.

Last time I had a weird reference, it turns out that the project file was of a specific type, and I had to change a GUID. (Yep, not clear).

Check your project GUID's.

Please go to Tools->Options->Source Control in Visual Studio, choose None as Current Source Control Plug-in, and then try again to see how it works.