Fix printer port in use error on Windows 10

If you see a “port in use” error when trying to print on Windows 10, the fix is usually to clear the stuck print queue, remove the old printer driver, and reassign the port. Follow the steps below to resolve it in about 10 minutes without third-party tools.

What causes the port in use error

The error typically appears when you try to add a printer or change its port, and Windows reports that the port (like USB001, COM1, or a network IP port) is already assigned to another printer. This often happens after a printer is unplugged while the spooler still holds a job, after a driver update fails, or when a previous printer entry wasn’t fully removed. The spooler service (the background process that manages print jobs) keeps a record of the port assignment, and if that record is corrupted or the queue is stuck, Windows refuses to reuse the port.

Before you start: check the basics

Try these quick checks first — they solve a surprising number of cases:

• Restart the printer and the PC. This clears many temporary spooler locks.
• Unplug the USB cable and plug it into a different USB port. Windows may assign a new port number automatically.
• Make sure the printer is set as the default (Settings > Devices > Printers & scanners).
• If it’s a network printer, verify it’s on the same Wi-Fi or Ethernet network and that its IP hasn’t changed.

Step-by-step fix: clear the print queue

The most common cause is a stuck job in the spooler. Here’s how to clear it:

1. Press Windows + R, type services.msc, and press Enter.
2. Scroll to Print Spooler. Right-click it and select Stop.
3. Open File Explorer and navigate to C:\Windows\System32\spool\PRINTERS. Delete all files inside this folder (you may need admin permission).
4. Go back to Services, right-click Print Spooler again, and select Start.
5. Try printing again. If the error persists, continue to the next section.

Remove the old printer and driver

If clearing the queue didn’t work, the port is likely still bound to a phantom printer entry. Remove it completely:

1. Open Settings > Devices > Printers & scanners.
2. Click the printer that shows the error, then click Remove device.
3. Now remove the driver: open Control Panel > Devices and Printers.
4. Right-click any empty area, select Print server properties (or “Server properties” on older versions).
5. Go to the Drivers tab, find the printer driver, select it, and click Remove. Choose “Remove driver and driver package” if prompted.
6. Restart your PC, then re-add the printer using the manufacturer’s installer or Windows’ “Add a printer” wizard.

Manually reassign the port

If the printer is still listed but the port is stuck, you can manually change the port assignment:

1. Open Control Panel > Devices and Printers.
2. Right-click the printer and select Printer properties (not “Printing preferences”).
3. Go to the Ports tab. You’ll see a list of ports with checkmarks.
4. If the port you want is already checked, uncheck it, click Apply, then re-check it and click Apply again.
5. If the port isn’t listed, click Add Port, choose Standard TCP/IP Port for network printers, or Local Port and type the port name (e.g., USB001). Then click OK.
6. Test by printing a test page.

When the error is on a network printer

Network printers often get a “port in use” error because the IP address changed or a duplicate port was created. Check the printer’s IP by printing a network configuration page (usually by holding a button on the printer). Then in the Ports tab, add a new Standard TCP/IP Port with the current IP, and remove the old one. If you’re using a print server, make sure the printer is shared with a unique share name and that the host PC’s firewall allows printer sharing.

Frequently Asked Questions

Why does the error say “port in use” when I plug in a USB printer?

Windows assigns USB printers a port like USB001, USB002, etc. If a previous printer entry still claims USB001, the new printer can’t use it. The fix is to remove the old printer entry and driver, then reinstall the new one — Windows will then assign the next available port.

Can I just delete the port from the registry?

Editing the registry is risky and usually unnecessary. The steps above (clearing the spooler, removing the driver, reassigning the port) are the safe, supported methods. If you do edit the registry, back it up first and only remove keys under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Monitors that you’re certain belong to the stuck printer.

What if the print spooler won’t restart?

If the spooler fails to start, check the Windows Event Viewer for error messages. Often it’s due to a corrupted driver or a file stuck in the PRINTERS folder. Try renaming the PRINTERS folder (to PRINTERS_old) and restarting the service — Windows will create a new one.

Will this fix work for a wireless printer?

Yes, the same principles apply. For wireless printers, the port is usually a TCP/IP port. Delete the old port and re-add it with the correct IP address. Also ensure the printer’s wireless settings are correct and it’s on the same network.

Do I need to reinstall the printer driver after clearing the queue?

Not always. If the driver is intact, just clearing the queue and restarting the spooler is enough. But if the error persists, removing and reinstalling the driver is the most reliable fix.

Is there a way to prevent this error in the future?

Always use the “Remove device” option in Settings before unplugging a printer, and avoid force-closing the print dialog. Regularly update your printer driver from the manufacturer’s website. Also, if you use a network printer, assign a static IP to it so the address doesn’t change.

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