SSDT Error Message: Unable To Cast COM Object of Type 'X' To Interface Type 'Y'

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

Problem

I got this error message at a client when I tried 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'

According to this source the reason could be a badly applied Service Pack or CU for example, but I’m not entirely sure about that in my case.

Solution

The solution for this is to reregister the dll that is referred to, in this case: dts.dll.
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 :)

@NickyvV