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An alternative solution that works for us is to use the "Schedule" setting to run it for 30m (to allow some leeway as the job takes a while), and then set the "Call Interval" setting to something very large like "999999". This is for an Inbound SQL adaptor. (If something goes wrong with this overnight run then we manually remove the "Schedule" setting and restart the Service. Once complete, we put back the setting ready for the next night.)