Vincenty-Excel VS Excel-Pomodoro-Timer

I suspect that your reason for asking this is that you've found that getting VBA to run every X minutes (using Application.OnTime?) will throw an error if VBA is already running, or if you're in the middle of editing a cell, etc. One way around this is, as u/e032 and u/Either-Belt-1413 point out, to create a further instance of Excel (InstanceTwo), with the VBA code running in a workbook loaded into that instance. There are a number of projects which demonstrate this - it's a very useful method - but the one that comes immediately to mind (and is most relevant to what you're doing) is the Excel Pomodoro Timer. When it is loaded, it creates a new instance of Excel in the background, and loads a userform with a pomodoro timer on it, which is then displayed at all times on top of any Excel workbook you're using without throwing any of the above errors. There are some much more complex and sophisticated methods using Win32 APIs - like this one - but that may be using a jackhammer to crack a wallnut.