I am using Visual Studio 2010. Some months back I was using some \'ABC\' TFS user to connect to TFS and mapped some folders on my local drive. Now my previous user \'ABC\' i
You need to get your TFS administrator to delete the workspace if you have no access to the account.
You may be able to do it by calling "tf workspace" with the explicit user specified, but you need "manage other users workspace" permission. TF Sidekicks uses the same commands so would require the same permission. It is a TFS admin productivity tool.
https://msdn.microsoft.com/en-us/library/y901w7se(v=vs.100).aspx
You can use:
tf workspace /delete "WORKSPACENAME;PREVIOUSUSERACCOUNT"