On a PC
At the bottom of the screen next to the clock, the Online Backup icon should be available if the program is running. The icon looks like a small padlock. When the program is running a backup, arrows will show instead of the padlock. If you do not find the icon, you need to check why the program is not running.
For Mac
In Mac OS X, check the application icon in the system tray in the upper right corner of the screen (next to the clock). The icon is a padlock. When the program is running a backup, arrows will show instead of the padlock. If you do not find the icon, you need to check why the program is not running.