We have a TFS 2005 server with some old code and I got VS2012. Should it be possible to connect to the TFS 2005 server from VS2012? Or do I need to install TFS explorer 2010?
TFS Compatibility Matrix - http://msdn.microsoft.com/en-us/library/vstudio/dd997788.aspx
According to the above link, neither VS2012 nor VS2010 can connect to TFS 2005.
You may need to use the MSSCCI Provider.