Printer prints pages on its own

Keep the stray pages, then look for a job log or job history on the printer's screen or on its built-in web page (type the printer's IP address into a browser). It often shows the time and source of each job, such as a computer name, an email address or fax.

On an all-in-one, incoming faxes print automatically when auto answer is on. In the fax settings, turn off automatic reports you don't need, such as a confirmation after every fax or a regular activity log. For junk faxes, turn off auto answer or use the blocking feature if your model has one.

If your printer has its own email address or is linked to a manufacturer account, anyone with the address or account access can send jobs. Sign in through the maker's official app or website, turn email printing off or limit it to approved senders, and remove users or devices you don't recognize.

Sign in to your router's admin page or app and look for port forwarding, virtual server or NAT rules that point at the printer's IP address, especially ports 9100, 631 or 515, which are used for printing. Delete any you don't need; home printing works without them.

UPnP lets devices open router ports automatically. If the router's list of UPnP mappings includes the printer, turn UPnP off in the printer's network settings, or on the router if nothing else you use, such as a games console, depends on it.

On the printer's built-in web page, set an administrator password if there isn't one and turn off remote or internet printing features you don't use. Then update the firmware from the printer's menu or the manufacturer's official instructions; updates often fix security issues.

On each PC that uses the printer, go to Settings > Bluetooth & devices > Printers & scanners (Windows 10: Settings > Devices > Printers & scanners), select the printer, choose Open print queue and cancel anything waiting. A laptop that was asleep sends its old jobs as soon as it reconnects.

If a deleted job prints again after every restart, run the command below in Command Prompt opened with Run as administrator. It stops the Print Spooler, deletes every waiting job file and starts the spooler again; your printers stay installed.

If this PC shares the printer, others on the network can print through it. Open Printer properties > Sharing and untick Share this printer if nobody needs it.

In System Settings > Printers & Scanners, select the printer, click Printer Queue and delete jobs you don't want. Do this on every Mac that uses the printer.

If this Mac shares the printer, other computers can print through it. Open System Settings > General > Sharing and turn off Printer Sharing if you don't need it.

If deleted jobs keep coming back, Control-click in the printer list and choose Reset printing system. It removes every printer and job, so add your printer again afterwards.