Same Workspace for VS2010 and VS2013?

Howdy,

I'm setting up TFS on a system and it appears that you can't have two version of Visual Studio map to the same directory on your local system.  I already have VS 2013 mapped to a local path.  When I go into Visual Studio 2010, connect to the TFS server and then try to map the path I get the message:

The working folder "C:\..." is already in use by the workspace ComputerName;UserName on computer ComputerName.

This doesn't make sense to me.  I can't have all my source in one local folder?  Won't this end up with duplicate copies of everything that is in the repository on my local hard drive?  Am I missing something here?

Thanks