I'm trying to create an OnResourceAvailable trigger for an Operator that runs once and then deletes itself so that it won't run again. Please see the attached model as a simplified example. On model reset, it adds an OnResourceAvailable trigger to Operator1, and that runs at time 30 when the Operator becomes available. The code then deletes the trigger using setnodestr. What seems to happen after time 30 is that it keeps running the code whenever the operator is available again (time 120, 210, etc. based on TimeTable1), even though the OnResourceAvailable trigger is now blank. This can be seen by stopping the model after the message box pops up at time 120 and looking at the triggers tab under the operator's properties. In my full model, the trigger is being added dynamically to an operator based on certain conditions, and I would like for it to run only once. I'm looking for a solution that does not use Process Flow if possible. Thanks for any help you can provide.