The 651 error is caused by a fault or incompatible network card / modem being unable to connect to the Internet or Local Area Network.
The issue is software related (not hardware) and is therefore relatively simple to fix, if you’re able to pinpoint the exact cause of it. This is – unfortunately – the thing that prevents most people from being able to resolve it properly… getting to the bottom of the error means that you have to try a number of other fixes.
The error mostly shows with the following message:
“Error 651: The modem (or other connecting device) has reported an error”
The main reason for the error to show is driver incompatibility.
Windows uses “drivers” to help it communicate with a number of different pieces of hardware, and are an essential element in the way the system works.
Unfortunately, the drivers that your system has will often become corrupted, damaged or out of date – leading various elements of a system’s functionality to become unusable or erroneous.
Whilst the error is quite old, the best solution is to re-install the driver then ensure that other aspects of your system are working as effectively as possible (IE not blocking the ethernet connection).
To fix the error, you first need to ensure that the driver is working properly, and then that you’re able to repair any of the specific causes of the problem (several files are known to present issues).
1. Update / Reinstall Driver
The first step is to update or re-install the driver for your ethernet card / modem.
To do this, you should restart into “Safe Mode with Networking” and then replace the driver:
- Click the “Start” button at the bottom left of the taskbar
- Select the “power” button from the left “charms” menu (icons)
- Holding SHIFT, select “Restart”
- This will open a blue Window from which you need to select “Troubleshoot” > “Advanced Options” > “Startup Settings” > “Restart”
- From the next Window, select “Safe Mode”
This will reboot the system into “Safe Mode” – basically allowing you to perform core system maintenance without third party software getting in the way.
- Right-click the “Start” button (bottom left of taskbar)
- Select “Device Manager”
- Scroll down to “Network Adapters”
- Right-click on the card which is causing issues and select “Uninstall”
- Follow the instructions on-screen
This will get rid of the hardware listing from your system – allowing you to manage the driver as you need.
From another system, you’ll then need to download the correct driver from the manufacturer’s website. Whilst you can get away with just restarting Windows (and letting it run the installation), it may put the wrong driver back on:
- Save the new driver to another system
- Use a USB flash drive to copy the driver to your damaged system
- Right-Click the card in “Device Manager” and pick “Update Driver Software”
- This will present you with two options – select the “Manual” one and choose the files you just copied via USB
After doing this, restart your PC into “normal” mode (just restart the system as you would normally).
2. Replace “rasppoe.sys”
Rasppope.sys is a file used to provide PPoE protocol functionality to Windows.
Located in C:/Windows/System32/Drivers, the file is used to provide PPoE connectivity, be it a modem or network card.
One of the problems with Windows 10 is this file becoming corrupted, incompatible or overwritten – preventing your system from being able to run the functionality required.
To fix this, you need to rename & replace it:
- Open Windows’ “File Explorer” (Start > left “charms” menu)
- Browse to C:/Windows/System32/Drivers
- Locate rasppoe.sys
- Rename to rasppoe_bk.sys
- Download a new version of rasppoe.sys from the web (Google “rasppoe.dll download” – look for “OpenDLL (.) com”)
- Place the new file in C:/Windows/System32/Drivers
- Restart PC
If the error still persists after this, you will also need to run Windows Update, run an antivirus scan and then remove any potentially conflicting software from your system.