Symptoms

Issue with K2 blackpearl for Visual Studio 2010 Components. Upon attempt to create or open K2 project the following errors are being displayed:
1. Upon attempt to create a new "K2 Empty Project":

“The ‘SourceCode.VisualStudio.WorkflowPackage, SourceCode.VisualStudio, Version=4.0.4.0, Culture=neutral, PubicKeyToken=… package did not load correctly.”

2. Upon attempt to open an existing K2 solution (which used to open fine earlier):

“iProject].K2proj’ cannot be opened because its project type (.k2prj) is not supported by this version of application”

3. Errors also present in AppDataRoamingMicrosoftVisualStudio10.0ActivityLog.xml
 

Diagnoses

This behavior can occue when you use K2 4.6.9 or any other K2 version prior to 4.6.11 which are not compatible with .NET 4.6 and such configuration (version of K2 earlier than 4.6.11 + .NET 4.6) is not supported. Please refer for details to K2 compatibility matrices:
http://help.k2.com/blackpearl/support-matrix
http://help.k2.com/smartforms/support-matrix

Resolution 

You have remove .NET 4.6 and revert to previously installed .NET 4.5 to resolve this issue.