Symptoms

After uninstalling, and installing all the K2 components on my laptop, it started working again.

But now I'm getting this error when trying to open the Start event on any workflow that is using SmartForms Integration: http://help.k2.com/kb001382

I have looked at the .kprx files and they all seem to contain the XML rows mentioned in that KB. I've tried to repair the SmartForm installation but no change.
“Value cannot be null. Parameter name: registeredPropertyWizard”

 

Diagnoses

This is a known issue similar to this KB http://help.k2.com/kb001382.
 

Resolution

The issue was resolved after following the following steps:
-Open the Well Maintenance Workflow Original.kprx in your favorite text editor (i.e. Notepad , I have to switch to XML format and use XML tool with line break plugin to make it a bit readable).
-Search for "SourceCode.Workflow.Design.Sharepoint15.ProcessDefinition.SPProcessPropertyWizardDefinition".
-Search for the last node in the "PropertyWizardDefinition" node.
-Ensure that the <WorkflowStartType>EventAndManual</WorkflowStartType> node exists, in addition to this one "<RegisteredItem>K2 for SharePoint Process Property Wizard</RegisteredItem>".
-If the nodes are not existed, add it manually