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Error 651: explanation and solution of the problem

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Windows error 651 - what happened?
How to fix error 651 in Windows
How to fix error 651 in Windows 7 and Windows 8?
Solution 1: restart your network device and computer
Solution 2: reinstall the network adapter driver
Solution 3: update the raspppoe.sys file
Solution 4: manually set the speed and duplex mode


Error 651: explanation and solution of the problem

On both personal and work computers, doing without Windows is almost impossible. Microsoft's operating system is included at no additional cost in most desktop computers, which is not only very convenient for individuals, but also for many businesses. Furthermore, when it comes to functionality and performance, the different versions of Windows would also leave little to be desired were it not for the sudden errors , the cause of which is rarely indicated in the warning message. 

One of these mysterious errors is 651 , which tends to appear especially in Windows 7, but also in newer versions, such as Windows 8 and Windows 10, when trying to establish a LAN connection. What is this connection problem and how can it be solved?

  1. Windows error 651 - what happened?
  2. How to fix error 651 in Windows
    1. Solution 1: restart your network device and computer
    2. Solution 2: reinstall the network adapter driver
    3. Solution 3: update the raspppoe.sys file
    4. Solution 4: manually set the speed and duplex mode
  3. How to fix error 651 in Windows 7 and Windows 8?

Windows error 651 - what happened?

Even if you have successfully connected your computer via network cable to the router or modem, failures in the Internet connection cannot always be ruled out. There could be, for example, configuration errors, outdated or missing drivers in the system - these problems could generate error messages at any time. One of the most well-known connection errors in Microsoft Windows 7, Windows 8 and Windows 10 systems is error 651, whose message usually takes the following form:

  Error 651: El módem (u otro dispositivo de conexión) ha informado de un error.  

In the latest versions, Windows 8 and Windows 10, error 651 is usually caused by a problem with a network adapter driver , that is, a driver for the hardware interface between the computer and the network device : usually be a poorly installed, outdated or missing driver. 

Also, especially in the older version, Windows 7, error 651 can be caused by RASPPPOE (RAS PPP over Ethernet). This universal driver is located in the system file raspppoe.sys and is often used in place of the official driver from the network device manufacturer, which can lead to problems if the file is corrupted..


In Windows 8 and similar versions, error 651 only occurs if the connection is established using a LAN cable . Wireless WLAN connections are exempt from this problem, so using Wi-Fi can be a temporary solution.

How to fix error 651 in Windows

Getting the 651 error message when establishing the connection is a clear indication that something is wrong with the communication between your computer and the DSL router or the intermediary dLAN adapter. The causes of this failure can be different, so there is no universal solution to the problem. Below, however, we present the four solutions with the highest probability of success to end error 651 in Windows..

Solution 1: restart your network device and computer

If you get error 651, before making any effort to check the controller status or network settings, try restarting the devices involved . To do this, unplug the router or dLAN adapter you are using for a moment and then reconnect it. The recommended waiting time is about 30 seconds .

If the problem persists, the solution may be to restart the computer . To do this, open the start menu (Windows icon) in Windows 10, click the? Start / Shutdown ? and then select the option? Restart ?:

Restarting your computer can be, as usual, the solution to error 651 in Windows.

Solution 2: reinstall the network adapter driver

In network communication, drivers have a very important role: for a device to connect to your computer via a LAN cable, the network adapter must have a suitable and updated driver package . While Windows 10 usually takes care of this automatically, the possibility that the driver software is outdated, corrupted, or even missing cannot be ruled out. Especially in the case of system updates it is not uncommon to come across such situations. The best and quickest response to this cause of error 651 is to reinstall the network adapter driver..


Only a user with administrator rights can install or uninstall the system drivers.

To carry out this task, the following steps must be followed:

  1. Open the ? Control panel ? via the start menu (Windows icon).
  2. In the list of items, select the? Device manager ?.
  3. Unfold the tab? Network adapters ? by clicking on the little arrow.
  4. In the list that will appear, right-click on the? Ethernet adapter ?, which is responsible for establishing LAN connections, and click? Uninstall ?.
  5. Then restart Windows 10. As soon as it boots, the system will automatically load and reinstall the driver software that was uninstalled. Another way to do this is to download the adapter driver directly from the manufacturer's website and install it manually.
The Ethernet adapter regulates the establishment of LAN connections between hardware elements.

Solution 3: update the raspppoe.sys file

As we have already mentioned, Windows can fall back on the universal RASPPPOE driver to use network adapters, so the raspppoe.sys file can also be the cause of network hardware failures . If Windows 10 displays error 651, this file may be corrupted. One way to replace corrupted raspppoe.sys file with An intact version of it, if you have a second Windows device with good access to the LAN, is the following:

  1. On the second Windows device, go to the ? \ Windows \ System32 \ drivers directory (found on the Windows partition).
  2. Copy the raspppoe.sys file (by right-clicking and then clicking Copy) to any external storage media , such as a USB stick or portable hard drive (right-clicking and then clicking Paste ).
  3. Then connect the external media to the computer where error 651 appears. Once here, again, go to the ? \ Windows \ System32 \ drivers directory and replace the file local raspppoe.sys for the intact file you just copied to external media.
  4. Finally, restart Windows 10.
In the Windows directory ?? \ Windows \ System32 \ drivers? you will find the files for the various system and device drivers.

If you are unable to access the raspppoe.sys file (that is, copy or delete it), you can get permission to do so as follows (provided you have administrator rights): 

  1. With the right mouse button , click the file raspppoe.sys .
  2. Select the menu? Properties ?.
  3. Go to the? Security ?
  4. Edit the access permissions of the user in question.

Solution 4: manually set the speed and duplex mode

If none of the solutions presented so far has been successful, you can still try by manually configuring your broadband connections. Specifically, it is a matter of establishing a minimum transmission speed of 10 Mbit / s ( full-duplex ) for LAN connections . Windows 10 actually allows up to 100 Mbit / s and even 1 Gbit / s.

To manually configure this minimum network speed, follow these instructions

  1. Open the ? Control panel ? through the start menu.
  2. Select the rubric? Network and Sharing Center ?.
  3. In the menu on the left, click? Change adapter settings ?.
  4. Right-click on the LAN connection that is causing the 651 error and choose the option ? Properties ?.
  5. Click? Configure ? and then go to the tab? Advanced options ?
  6. From the list of options, select? Speed ​​and Duplex Mode ?, where you can indicate the desired value (minimum of ten Mbit / s full-duplex ).
You can also access the? Network and Sharing Center? Windows 10 by opening the application? Run? and entering the command ncpa.cpl.

How to fix error 651 in Windows 7 and Windows 8?

LAN connection failures are not unique to Windows 10: error 651 is also very common in Windows 8 and in its predecessor version, Windows 7, when there are communication difficulties between the computer's network hardware and the router or modem to which it is connected. If you are using one of these operating systems and you want to get rid of this error, you can simply rely on the four solutions explained above for Windows 10 - the best working methods to get rid of error 651 in Windows 7 and Windows 8 are the same :

  1. Restart the network device or computer
  2. Update or reinstall the network adapter driver software
  3. Replace the current version of the raspppoe.sys file
  4. Manually configure broadband speed

Microsoft stopped offering security updates and technical support for Windows 7 on January 14, 2020, with the exception of paid support for businesses, which runs until 2023. If you are not a user of the latter, it is highly recommended that you replace your version Windows to a newer one . In our article on Windows 7 end of support we tell more about it.