Complete the following steps to verify the drum and toner are inserted correctly, and the top cover is closed securely on both sides:
Raise the top cover by pulling the lock tab (located on its underside) toward front of the unit and lifting the cover until it is completely open.
Remove the drum unit by lifting its handles slightly, then pulling it out. Check for and remove any foreign objects that may have accidentally fallen inside.
Reinstall the drum unit into the machine.
Lower the top cover until the lock tab clicks, making sure it is evenly closed on all sides.
If "Cover Open" continues to appear, please contact the Brother Service Center near you.