When I load Visual Studio 2012 up, it will attempt to connect to the previous TFS server that it was connected to.
On one of my machines (that also happens to connect to occasionally TFS2008 and TFS2010 servers) always seems to default to completely the wrong account for connecting to Visual Studio Online (tfspreview), and if I were to try and get the latest version, it'll give an error of the form:
Microsoft Visual Studio
Source Control Explorer
TF204017: The operation cannot be completed because the user (Account Service ([my tfs server]) does not have one or more required permissions (Use) for workspace [my workspace];[my live id].
OK
How can I influence Visual Studio 2012 to default to the correct credentials, rather than a seemingly fictional Account Service one?
I had a very similiar problem as I was not able to connect to TFS with my own credentials. Turned out that the user who had created the image (I was using Hyper-V) stored his account in Credential Manager. There was no way to change this in Visual Studio. To solve the issue, I opened Credential Manager in Control Panel and edited the Generic Credentials to be my own account. I closed and opened Visual Studio 2012, and reconnected to TFS. It prompted me for my credentials, but it connected with my account from then on.
hope this helps, sivilian