The Phantom Printer Queue
macOS uses a networking protocol called Bonjour to automatically discover and advertise services on your local network, including shared printers. If a colleague or flatmate adds a new printer to the same Wi-Fi network, macOS will silently detect it and add it to your list of available printers in System Settings. In corporate environments, this can result in dozens of printers appearing in your print dialogue — printers on different floors, in different departments, or even decommissioned devices still broadcasting their Bonjour service. Selecting the wrong printer from a crowded list and accidentally sending a confidential document to a public lobby printer is a genuine risk.
Preventing Automatic Printer Discovery
To stop macOS from automatically adding every printer it discovers via Bonjour to your printer list, you must disable the automatic discovery feature in the printing preferences.
Click the Apple Logo in the top-left corner and select System Settings. In the left-hand sidebar, click on Printers & Scanners. Review the list of currently added printers. Right-click (or Control-click) on any printer you did not add manually and select Remove Printer to clean up the list. To prevent future automatic additions, macOS does not offer a single toggle for this, but you can control it by resetting the printing system. Right-click anywhere in the printer list area and select Reset printing system…. Confirm the action. This removes all printers. Now, manually re-add only the specific printers you actually use by clicking the + button, selecting the IP tab, and entering the printer’s direct IP address rather than relying on Bonjour discovery. Printers added via IP address are persistent and static — macOS will not automatically add or remove them based on network broadcasts.