When using the K2 Designer for Visual Studio, and particularly a solution that contains InfoPath form templates, you may receive the following error:
You may see this error if you have built a single complex solution, or have built multiple solutions using a single namespace.
The resolution is to save your project and close Visual Studio, then delete all items in the temporary folder. Visual Studio may be using the system temporary folder or the user temporary folder. You can check this by typing %Temp% on the Run line and pressing Enter. This will open a Windows Explorer window to the current temporary folder. If you see a SourceCode.Workflow.InfoPath.Temp folder in this location, delete it and then restart Visual Studio. If you do not see this folder, you can delete all folders and files in this temporary location and restart Visual Studio to see if the problem is resolved. If the problem is not resolved, browse to the alternate temporary file location (either system or user) and delete files in this folder, and then restart Visual Studio.
When removing files from the temporary folder, you should first shut down all running applications. It is also recommended that you restart your computer after removing these files, once you have confirmed that the error in Visual Studio is resolved.