In what action does the child job pauses? Is it the same action every single time? The exception handling system should not help you in this case since it only kicks in if an error occurs and from your description there is no error at all: the job just pauses in a specific action. In order to figure out the action where the job hangs, you need to keep an eye on the notification window.

I have gone the long way about this, I have disabled the child job line by line until I have worked out what stalls the program.  I have pinpointed it to this IF statement -

IF WINDOW - If window 'Are you sure?' is open
  Send mouse click to X,Y co-ordinates (Relative to active window)
END IF

If I disable the first and last line then the mouse clicks every time, but if re-enable the 2 lines it sometimes stalls the program.  As I stated in the original post it works for about the first 10-15 times and then stops for no apparent reason.

Hello,

This sounds like a very weird issue that you are facing. Can you please export the jobs (the parent and the child) and send them to us at support@winautomation.com ?

If you can do that, we will be able to figure out what the specific problem is.

...It's funny, I've had some jobs recently start to stall too - I'm thinking this may have to do with the coordinates of a website changing perhaps.....

 If you are using coordinates, then there is a chance that the problem is related to the coordinates being changed. Recapturing the coordinates (with the Mouse Over + Control method) will tell you if this was the problem. I personally tend to use the image recognition more often, so, whenever something fails I always know exactly in which part of the automation process the job has stalled.