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Alright, Attached you'll find a zip of the current project I'm writing. I've got an insane error where an "error" message (a simple string + variant cluster) is loaded into a control queue. When previewed before dequeued, it shows up fine, when dequeued proper it's blank and causes a meltdown. Steps to reproduce: 1) Fire up "Main Separate Sub VI" 2) Run the Code 3) Look for "Start Calibration VI" on the front panel, bottom left hand side, under a comment that says "Debugging commands only" and hit the button. 4) Watch the sparks fly... 5) Use the abort button to kill the code Note: I think I've set up the VI path right for the calibration VI, if not, change it to an absolute path which points to wherever it ended up. So the error you should see, is that a pop up appears saying "The case does not exist in the Sub VI Control Loop please check your spelling" which is my default typo handling case. What's happening is that the calibration VI is looking for a data queue it can latch onto, as it can't find any, it registers an error with the host code, passing the error code along with it's name back to the host. The error code is then loaded onto the common error handling line of the "Sub VI Status Handling" loop and caught by the error handling case at the end of each iteration of that while loop. This is when things get funky. As mentioned above, the enqueue operation doesn't time out, the "Error+Variant" data message is loaded onto the queue, when the queue is previewed shortly before it's supposed to be dequeued, it shows the element contained within (the "Error + Variant" thing). Once dequeued the message is blank, causing the loop to go into it's default typo handling behaviour. So my question is obvious I guess. Why in the blue blazes is the "Error" string blank upon dequeue?! P.S. As a quick side note, I use the exact same method of catching errors within the Calibration Sub VI in it's own control queue. It works clearly as this is how the error is caught and passed back to the host code in the first place. Queue Error Example.zip