A new developer installed the TEE plug-in into Eclipse. Because he hadn\'t yet been granted access, he borrowed my login and username. Now that he has been granted access, is
Unfortunately, TFS workspaces are created per-user. If the new developer were to sign in as himself, he cannot load the TFS workspace that he originally used (impersonating you), and the TFS plug-in for Eclipse will not be able to connect his Eclipse projects to TFS. He'll need to set up a new TFS workspace with the appropriate working folder mappings (the same as the one he's using now).
This can be done manually, but it's probably far easier to simply create a new Eclipse workspace and import the projects again. There's no need to reinstall Eclipse or the Team Explorer Everywhere plug-in in order to accomplish this, but he does need to reconfigure his profiles (the mechanism used to store connection information in Team Explorer Everywhere 2010.)
He should perform the following steps in order to start over (and authenticate as himself):
Delete the TEE profile configuration and the workspace cache - the profile configuration has profiles with your authentication, and the workspace cache has a list of your workspaces (with the profile information that is used to connect to them). The profile configuration file is:
%LOCALAPPDATA%\Microsoft\Team Explorer\10.0\Profiles\profiles.xml
The workspace cache file is:
%LOCALAPPDATA%\Microsoft\Team Explorer\10.0\Workspaces\workspaces.xml
Restart Eclipse, and import the necessary projects from TFS. At this point, he should be prompted to authenticate, and should be able to do so as himself.
Note: this mechanism is a bit different in TEE 2012 - we've removed profiles for simplicity. If you want to authenticate as a different user, we will respect the Windows credentials storage mechanism just like Visual Studio and Internet Explorer. (Available in Control Panel -> Manage Windows Credentials.)