Symptoms

When we try to open and edit some K2 views in K2 Designer, we get the following error message:

Server Error
Value cannot be null
Parameter name: s

We found the following article regarding this topic (http://community.k2.com/t5/K2-blackpearl/Value-cannot-be-null-Parameter-name-s/ta-p/74500) so we already regenerated Smart Objects since they were out of sync for the respective SharePoint list. Moreover, we restarted the K2 Service. Unfortunately, the problem still comes up so that we are not able to open and edit these views in K2 Designer. Users can, however, use the respective forms, which contains these views, to create new requests without problems.

 

Diagnoses

As a start, the SmartObject logs were supplied to analyse what exactly happens during execution of the SMO's on the Views. Since this issue would require deep troubleshooting and diagnostics processes, Labs requested the following info:

• Repro steps (can you remember changing anything before this broke)
• Backup of your K2 DB
• Service instances that get used for the SmartObjects
• STP’s or WSP (SharePoint) (if applicable)
• Custom DLL’s if used in workflows

Before sending this info, the customer decided to delete and recreate the views so we didn't investigate further, but it would probably have involved finding the GUIDs for the broken Views and correcting them in a different table (this is my speculation).

 

Resolution

At the end of the day we decided the quickest solution was to rebuild these Views from scratch to avoid lengthy troubleshooting / diagnostics processes.

There is most likely a way to resolve this issue without recreating the Views, but that would involve analyzing the K2 database and making changes in SQL etc.