iRobot defines Error 520 as a failure to communicate with the dock over infrared (IrDA). The support page names Roomba Plus 400, Plus 500, Plus 600, Max 700, and Max 800 Series. Confirm the complete robot and dock model before using these checks; the page does not list every dock or firmware pairing.
This alert may appear when the robot circles near the dock, does not connect or begin evacuation, or does not respond to the HOME button. It does not by itself prove that the infrared sensor or dock has failed.
Check the infrared path
Follow the iRobot page in order:
- Move nearby devices that use infrared away from the dock.
- Clear objects between the robot and dock.
- Wipe the infrared windows on both the robot and dock.
- Send the robot home again. If it still will not dock, place it on the dock with the charging contacts aligned.
If Error 520 remains, iRobot directs owners to reboot the dock and robot, then retry docking. Unplug the dock for a few seconds and plug it back in. Reboot the robot using the instructions for its exact model or app; iRobot’s listed button sequence for the named families is not a universal Roomba reset.
Contact iRobot Customer Care if the error continues after the documented checks. For a warranty claim, the support page asks for the robot, serial number, and proof of purchase. Have the exact alert, robot and dock models, and checks already tried ready.
Keep the alert in context
Error 520 here is a dock communication alert for the listed Roomba families. Do not apply the number or recovery steps to another Roomba series, another iRobot alert, or another brand. For other docking messages, see Roomba Error 1010 dock and navigation checks and the alert identification workflow.