I was experimenting with the ontime property as part of a development and found that i couldn't always disable it
This was the rescheduling section :-
Cnext = Now() + TimeValue("00:01:00")
Application.OnTime Cnext, "UpdateClock"
This was the disable
Application.OnTime EarliestTime:=TimeValue(Cnext), Procedure:="UpdateClock", Schedule:=False
Sometimes it works, sometimes it doesn't ... Any ideas?