Why did my printer stop working after I changed my router?

This catches people every time they switch provider, replace a router or move house. Nothing is broken: a printer holds exactly one set of wireless credentials, permanently, and there is no mechanism by which it learns that the network it knew has been renamed. The frustrating part is that many printers give no useful error — they simply stop appearing.

Step by step

1. Decide whether to reuse the old network name.If you can set the new router to the same network name and password as the old one, every wireless device in the house — printer, television, smart plugs, thermostat — reconnects on its own and there is nothing else to do. This is by far the easiest route and it is worth doing before you change anything else.
2. Otherwise, re-run the printer's wireless setup.On a printer with a screen, this is under network, wireless, or wireless setup wizard. It scans for networks, you pick the new one and enter the password. Take care with the on-screen keyboard — a mistyped password is the commonest failure here.
3. Use WPS if both devices have it and you prefer buttons.Press the WPS button on the router, then the wireless or WPS button on the printer within two minutes. Convenient, though some routers now ship with WPS disabled for security reasons.
4. Use a USB cable temporarily if the printer has no screen.Connect it to a computer by USB, run the manufacturer's setup utility, choose to configure wireless, give it the new details, then unplug the cable. The printer keeps the wireless settings.
5. Watch for the 2.4 GHz trap.Many printers are 2.4 GHz only. If the new router presents both bands under one name and your phone is on 5 GHz, an app-based setup can fail. Force the phone to 2.4 GHz for the setup.
6. Print a configuration page and note the new address.Once it is on the network, get its address from its own front panel report. You will need it for the next step and it is worth keeping.
7. Remove and re-add the printer on every computer.The stored queue entries point at the old address. Delete them all and add the printer once by its new address. Do not leave old entries in place — they cause the offline flag to reappear.
8. Reserve the address on the new router.Set a DHCP reservation for the printer's hardware address. It costs two minutes now and means the printer never wanders again.

Tips

• Before changing a router, walk round and list every device that connects wirelessly and has no screen — printer, plugs, bulbs, doorbell, thermostat, weighing scales. Those are the ones that will need attention, and the list turns a lost afternoon into an hour.
• Keeping the old network name and password on the new router is the single best trick in home networking. There is no technical reason not to, as long as the password is a strong one.
• If you also changed provider, check whether the new router has client isolation or a strict firewall setting enabled by default, which can block printing even after the printer joins.

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