Count Down Timer - force times out when using another workbook

Hello fellow Excel nerds like me,

I built this workbook that has a count down timer for my employees (so that they can keep track of their own time spent on certain projects). This is the rough draft, and it's working great...except whenever I toggle to another excel work book (alt + tab) the "time is up" pop-up message box appears prematurely and pauses the timer. You might have to try it out for yourself to see what I'm talking about. Keep a seperate excel work book open while you also have mine open, and toggle to the other spread sheet.

This also happens when the timer is running and then I open a new work book seperately. I'm not sure if there's anything different I can do in my coding to prevent this or if I'm just going to have to live with this glitch. See attached file.

Thanks for any help! I love this forum!


CountDown Timer (test).xlsm