"No such interface supported" after upgrading SourceSafe project to 2012 SSMS format.
Microsoft has logged this issue:
http://support.microsoft.com/kb/2727824

and has included the fix starting in the following update:

2723749 Cumulative update package 3 for SQL Server 2012

According to Microsoft, this fix should be available in Service packs:


  Microsoft SQL Server 2012 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2012 Service Pack RTM hotfix to an installation of SQL Server 2012 Service Pack RTM. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.


So, the latest SQL Server 2012 service pack contains the fix, and it worked for me.