Does a system tray app only work when a user is logged in?

My system tray application only work when any user is logged in. I want that it should run all the time irrespective to user login. should i change the approach.

If you want an application to run without requiring a user to be logged in, use a Windows Service (assuming your question refers to Windows).

Right approach for such application is to have a system service with a business logic and a "tray" application used for notifications and other user interaction. The reason is that system service can't talk to the user (without certain tricks which are limited and not always suitable).