I had faced the similar problem, I could not connect to TFS with my credentials. Later on I figured out that the user who had created the image (Using Hyper-V), stored his account in the Credential Manager.
It could never be resolved using the Visual Studio. In order to solve this, I had to open Credential Manager in my control panel and then I had to edit the Generic Credentials to be my own account. I then closed the visual studio 2012, and then opened it again, and the again connected it with TFS.
It will prompt you towards your credentials.