Class not registered error in SSAS Data Source View
You have either installed an older version of SSDT/Visual Studio side by side with your 2015 visual studio or you are trying to open a data source view created in a newer version of SSDT/Visual Studio.

Some binary data stream is written in the .dsv file and includes the version information. The solution is to install a recent enough version of Visual Studio or SSDT and possibly re-register DDSShapes.dll.

See this MSDN post for details which explains:


  If you try to use SQL Server 2012 version of the SQL Server Data Tool
  to open the DSV modified by the SQL Server 2014 version of the SQL
  Server Data Tool, you gets this COM exception. The reason is, this
  leading 4 characters of binary data is the version of ATL used to
  compile the DDSShapes.dll. When this DLL reads the binary data, it
  check if the version of the ATL that was used to save the data, making
  sure it is below the version recognized by the DDSShapes.dll. "000a"
  is a higher value than "0008", so the SQL Server 2012 version of the
  SQL Server Data Tool throws an exception.
  
  The solution is to install the SQL Server 2014 version of the SQL
  Server Data Tool from https://msdn.microsoft.com/en-us/data/hh297027 .
  You should get the new version of the DDSShapes.dll in C:\Program
  Files (x86)\Microsoft SQL Server\120\Tools\Bin.