Symptoms

Unable to open K2 projects using K2 Studio on the client/developer machine with the following error message:

Exception has been thrown by the target of an invocation

Sample error message screenshot:

The same projects can be opened from another client/developer machine.
 

Diagnoses

Check that K2 version on the client/developer machine is aligned with K2 version on server. In case it does not uninstall old/incorrect version on the client, perform system reboot and install exactly the same version as on your K2 server. Perform reboot after installation of proper version too.

Other possibilities here is installation of K2 client components on top of incompatible/not supported by K2 base OS or on top of OS with incompatible version of .NET installed.
 

Resolution

Install correct version of K2 components (matching server-side components).