What do it mean when flies are in your window seal when you kill them they come back?

If flies are consistently returning to your Windowsill, it may indicate an underlying issue such as a breeding site nearby or a food source attracting them. Killing individual flies may help temporarily, but it won't solve the problem if the source of attraction isn't addressed. It's important to identify and eliminate any potential attractants, like garbage or decaying organic matter, and to ensure that Windows and doors are properly sealed to prevent their entry. Regular cleaning and possibly using insect traps can also help manage the situation.