Design time error dropping components on form

Visual Studio 15.9.4, Infragistics 17.1

Whenever I try and add a new Infragistics component to a form in the project I get the following error (translated from Italian!) 

"Can't create the component "AnyInfragisticComponent". Error message: System.Runtime.InteropServices.COMException (0x8004D745) The project already contains a refrence to the component "Infragistics4.Win.Misc.v17.1" etc.

Looking at the forum I've tried various "solutions" (emptying license.licx and recompiling etc) nothing seems to make any difference. I don't know if it's relevant but the context menu for UltraToolbarsManager doesn't appear any more either.

Thanks 

Ian.

Hello Ian,

Thank you for contacting Infragistics!

Concerning the error you are getting it seems like the version in your toolbox is different than the version you have referenced in your project, like you updated to a later service release. You should be able to resolve this by updating your project references to reference the newer dll or change the references to be specific version false.