SSDT Error Message: Unable To Cast COM Object of Type…

Just a short blog post today explaining a problem (and solution) I ran into when working at a client recently. Hopefully it is helpful for anyone out there.

Problem

I recently got this error message at a client when trying to open an SSIS solution in SSDT.

Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.SqlServer.Dts.Pipeline.Wrapper.IDTSObject100'

The reason could be a badly applied Service Pack or CU for example, but I’m not entirely sure about that (source).

Solution

Before starting, make sure you close any open Visual Studio instance.
In a Command Prompt go to the following path (be sure to start the Command Prompt as Administrator):

C:\Program Files\Microsoft SQL Server\120\DTS\Binn\

where 120 is you SQL Server version number.
Reregister the dts.dll by executing the command:

regsvr32 dts.dll

If all goes well you should see the following message pop up:

I found info here.

Happy coding :)