If your printer works but the scanner does not after a new modem, the multifunction device is probably not half-broken. Printing and scanning can use different software, network addresses and communication methods. Restoring the print queue does not necessarily repair the scanner connection.
This often happens after replacing an ISP modem, installing a new router, changing internet providers or moving the printer onto a different Wi-Fi network. The printer may produce documents normally while Epson Scan, Brother iPrint&Scan, Canon IJ Scan Utility, HP scanning software or the computer’s built-in scan application reports that no scanner is available.
The important clue is that scanning stopped after the network changed. That points away from the scanner glass, document feeder or image sensor and towards the connection between the multifunction printer and the computer.
For broader printer and scanner connection help after a modem replacement, PcRiot can check the modem, multifunction printer, scanner software and every computer that needs to use it.
Printing and scanning are separate network functions
A multifunction printer may look like one device, but your computer does not necessarily communicate with every part of it in the same way.
- 🖨️ Printing may use an existing print queue. Windows or macOS can send documents through a TCP/IP port, WSD connection, AirPrint connection or manufacturer driver.
- 📄 Scanning may use separate software. The scan utility may search for the device independently or retain its own saved network address.
- 💻 Scan to computer works in the opposite direction. The printer must know which computer is available and the computer must be running software that accepts the incoming scan.
- 📁 Scan to folder uses another destination again. It may depend on a saved computer name, network share, username, password and folder path.
One connection can therefore survive the router change while another fails. A working printout proves that the printer can perform its basic printing function. It does not prove that the scanner software is communicating with the correct network device.
The scanner software may still have the old network address
A new modem commonly assigns the printer a different local IP address. For example, the old router may have placed the printer at an address beginning with 192.168.0, while the new router uses a range beginning with 192.168.1.
The print queue may rediscover the printer automatically, or someone may have already removed and re-added it. The scanner utility can remain attached to the printer’s previous address.
This can produce a confusing combination:
- ✅ Documents print normally from Word, email and PDF applications.
- ❌ The manufacturer’s scan utility says the scanner is unavailable.
- 🔍 Searching for scanners either finds nothing or shows an obsolete copy of the device.
- 🔁 Restarting the printer temporarily changes the error but does not restore reliable scanning.
The correct repair may involve removing the saved scanner entry, discovering the multifunction device at its current address and confirming that the utility is using the network scanner rather than an old USB, hostname or IP-based entry.
When the scanner software cannot discover the multifunction device at all, first check whether the computer can see the printer on the new network. A discovery or network-isolation problem can affect scanning even when an existing print queue continues to work.
Scan-to-computer registration may have been lost
Scanning from an application on the computer and selecting “Scan to Computer” from the printer’s control panel are not always the same process.
For scanning initiated at the printer, a manufacturer utility may need to run in the background and register the computer as an available destination. The printer then displays that computer by name.
After a new modem or router, that registration can fail because:
- 🌐 The computer is now identified on a different local network.
- 🧱 The firewall treats the replacement network as public and blocks incoming scanner communication.
- 🛑 The manufacturer’s background scan service is no longer running.
- 📛 The computer name shown on the printer refers to an old installation or a computer that is no longer available.
- 📶 The printer and computer are connected to different, isolated or guest networks.
The printer may continue showing the old computer name even though that destination no longer responds. Re-enabling scan-to-computer normally requires more than confirming that the printer itself is connected to Wi-Fi.
TWAIN, WIA and manufacturer scan utilities can behave differently
Windows scanning applications commonly communicate through technologies such as TWAIN or Windows Image Acquisition, usually called WIA. Manufacturers also install their own discovery services, drivers and scanning applications.
You do not need to understand these standards in detail to diagnose the pattern. The important point is that different applications can reach the same scanner through different software paths.
For example:
- 1️⃣ The manufacturer’s application may find the scanner while Windows Scan cannot.
- 2️⃣ Windows may list the multifunction printer but expose only its printing function.
- 3️⃣ One program may retain the previous scanner address while another rediscovers the current device.
- 4️⃣ A basic driver may support printing but omit the full network-scanning components.
This is why repeatedly removing only the Windows printer queue may not fix the scanner. The relevant manufacturer scanning package, scanner driver or device-selection utility may also need to be repaired or reconfigured.
Firewall permissions can block scanning but allow printing
When Windows connects to a replacement router, it may identify the Wi-Fi or Ethernet connection as a new network. If that network is classified as public, Windows applies more restrictive discovery and firewall rules.
Existing outbound printing may continue because the computer is initiating communication with the printer. Scanner discovery and scan-to-computer features can fail because they require additional local-network traffic or an incoming connection to the computer.
Possible signs include:
- 🧱 The scanner appears when the firewall is temporarily disabled but disappears when it is restored.
- 🔒 The manufacturer utility asks for local-network or firewall permission after being reinstalled.
- 🏠 Changing the Windows network profile from public to private restores local discovery.
- ↔️ Scanning works when started from the computer but not when initiated from the printer panel.
The permanent fix is not to leave the firewall disabled. The correct local network should be trusted where appropriate, and the required scanner applications and services should have suitable permissions.
Scan-to-folder may still point to an old computer or address
Home-office and small-business multifunction printers may send scans directly to a shared folder on a Windows computer, Mac, server or network storage device.
A modem replacement can break this even when ordinary printing survives. The printer may still contain:
- 📍 The old computer IP address.
- 🖥️ A computer name that no longer resolves correctly on the new network.
- 📂 A shared-folder path that is no longer accessible.
- 👤 Saved credentials that are no longer accepted.
- 🚧 A destination located behind a second router, guest network or isolated mesh segment.
Testing the printer’s Wi-Fi connection alone will not reveal these problems. The destination computer or storage device must also be reachable, the folder must still be shared, and the printer’s saved address-book entry must point to the correct location.
The scanner may work on one computer but not another
When one computer can scan successfully, use it as the diagnostic control. It proves that the scanner hardware and at least one network path are working.
Compare the working and failing computers:
- 📡 Network: Are both computers connected to the same main network rather than guest Wi-Fi, an extender network or a secondary router?
- 🧩 Software: Do both have the full manufacturer scanner package, or does one have only a basic print driver?
- 🎯 Selected device: Is the failing computer trying to use an obsolete scanner entry or the printer’s former IP address?
- 🛡️ Permissions: Does the failing computer have different firewall, security or local-network settings?
- ⚙️ Background services: Is the scan-to-computer utility running and registered on both machines?
The same principle applies when the printer or scanner works from a phone, Mac or one Windows computer but not another. The working device shows that replacement hardware is unlikely to be the first answer. See how to diagnose a printer or scanner that works on one device but not another after a router change.
Repair the scanner connection in a controlled order
Changing several modem, printer and computer settings at once can make the result harder to understand. A controlled sequence is safer.
- 1️⃣ Confirm the trigger. Verify that scanning stopped when the modem, router, Wi-Fi name, password or internet provider changed.
- 2️⃣ Confirm the printer’s current network. Check that it is connected to the intended home or business network and has a valid current address.
- 3️⃣ Test scanning from the computer. This separates general scanner discovery from scan-to-computer registration.
- 4️⃣ Check the selected scanner. Remove or replace obsolete scanner entries that refer to the previous network.
- 5️⃣ Repair the manufacturer utility. Confirm that the correct scan software, driver and background services are installed and running.
- 6️⃣ Check network and firewall permissions. Make sure local discovery is permitted without unnecessarily disabling security.
- 7️⃣ Re-register scan-to-computer. Remove obsolete computer destinations and register the current computer again.
- 8️⃣ Test every required workflow. Test scanning from the computer, scanning from the printer panel and scan-to-folder where those features are used.
This order avoids treating a scanner-software problem as a Wi-Fi compatibility fault or repeatedly resetting a printer that is already connected correctly.
Do not stop when the first page prints
A test print is useful, but it is not proof that a multifunction printer has been fully restored after a network change.
A complete repair should test the functions the household or business actually uses:
- 🖨️ Printing from each required Windows computer or Mac.
- 📱 Printing from phones or tablets where required.
- 🖥️ Scanning from the manufacturer utility or normal computer application.
- 🔘 Starting a scan from the printer’s control panel.
- 📂 Sending scans to shared folders or other saved destinations.
Otherwise, a basic printer reconnection can leave the customer with only half of the multifunction device working.
PcRiot can restore both printing and scanning
When printing works but scanning stopped after a modem replacement, PcRiot can check the complete connection rather than treating the printer, router and computer as unrelated devices.
This can include identifying the printer’s current network address, removing obsolete scanner entries, repairing manufacturer scan utilities, restoring TWAIN or WIA access, correcting firewall permissions, re-registering scan-to-computer and updating scan-to-folder destinations.
PcRiot provides onsite Perth printer and scanner support after modem, router and Wi-Fi changes. The job is not considered complete merely because one test page prints. Printing and scanning should work from the devices that actually need them.