Simple VBA running clock macro that I can't seem to stop without forcing an error

Hello all,

Windows 10 Pro, MS Office 2010, Excel.

I have a simple VBA macro that starts a running clock in a cell. Below is the code that works to insert a running clock in "My_ClockSheet1, Cell A1" that refreshes every second.

Sub UpDateClock()
' *** Change Sheet name and Range reference to suit ***
Worksheets("My_ClockSheet1").Range("A1").Calculate
Application.OnTime Now + TimeValue("00:00:01"), "UpdateClock"
End Sub

It won't stop unless I open a seperate workbook, forcing a Script out of range error due it seems to the opening workbook not having a sheet of the same name. I hit End in the error window, the clock stops and I can save and close the workbook as normal. Seems like it should be easy but everything I've tried doesn't seem to work. When saving the document and closing, it just pops back open. When I try to execute an Esc key hit after saving and closing, it's hit or miss if the timing is right, more miss than hit.

It is easy to put a button pointing to UpDateClock sub or even a call from another macro. I want a clickable button to stop the clock whenever needed.

Thanks in Advance for any help,

Bud,