Time Out icon Time Out
You deserve a break

How can I stop the window appearing after restarting my Mac?

The Time Out preferences window always appears when opening the app from the Finder, but when you restart your Mac, the window should not appear, even if it is launched via the Automatically start Time Out… preference.

If it does unexpectedly appear after you restart your Mac, the most likely reason is it was launched either by Login Items or the Dock.

To check the Login Items, go to System Preferences ▸ Users & Groups ▸ Login Items, and see if Time Out is listed. If it is, remove it.

If that doesn't solve it, check the Dock: show the Time Out icon in the Dock if it isn't already (via the General preferences), then click-and-hold on its icon in the Dock to show the menu, and look at Options ▸ Open at Login. Uncheck that if checked.

To ensure you don't miss your breaks, make sure the app is launched by checking the Automatically start Time Out… preference on the General page. (Note that this will only work if the app is within your Applications folder.)