Issue Description

When logging into K2 Designer or any runtime URL using Forms STS authentication an error occurs.

Error Message

The error states: “An item with the same key has already been added”.


The error occurs while the security label methods are loaded. The current execution thread had not finished processing yet when the next thread tried to add the security method for a second time.


  1. Ensure you have K2 Five installed.
  2. Get the K2 Five FP4 from Regional Support.
  3. Install the K2 Five FP4 to apply the fix.