Normally, when you switch on your computer, the Windows OS is loaded, along with the hundreds of files, processes, and services required for Windows to run properly. However, sometimes, the system might be unable to boot normally and instead throw the ‘The operating system cannot be booted because of important system driver errors’ error message.

The error message reads in full:

‘The operating system couldn’t be loaded because a critical system driver is missing or contains errors.

File: \windows\System32\drivers\qevbda.sys

Error code: 0xc0000221’

The error notification suggests a solution that involves using recovery tools. In our Windows tutorial today, we explain how to fix system driver errors in Windows 10.

Usually, the qevbda.sys file is to blame for the error. The file, which is located in %Windir%\%System%\drivers, is associated with QLogic FastLinQ Ethernet, a product of Cavium, Inc.

How to Remove the “The Operating System Cannot Be Booted Because of Important System Driver Errors” Notification

Solution 1: Check for Faulty Connected External Devices

If one of your connected peripheral devices is problematic, you may encounter a boot-time error. These include devices like your external hard disk drive, USB hub, mouse, or keyboard. To check for the faulty device, unplug all the devices and try booting Windows. If it boots normally, try plugging in the devices one by one until you find the culprit.

Solution 2: Check Your System for Driver Issues

Device drivers play a crucial role in enabling your Windows operating system to function correctly. If any hardware installed or attached has outdated or corrupted drivers, you’ll encounter driver issues. That’s why keeping your drivers updated is fundamental to seamless PC operation.

Otherwise, you may run into multiple issues, including application freezes and crashes, software incompatibilities and conflicts, hardware failures, system instability, your PC failing to boot into Windows, and so on.

Since your PC is not booting normally, you will have to install compatible drivers in Safe Mode. To boot into Safe Mode on a Windows 10 machine, follow these steps:

  1. If your computer is turned off, press the power button to turn it on. Just when your PC shows signs that it’s starting (when the Windows or your manufacturer’s logo appears on the screen), hold down the power button until the device turns off.
  2. Repeat this process three more times and allow your PC to fully restart on the fourth attempt. You will enter winRE.
  3. Now, to enable Safe Mode, choose “Troubleshoot” on the “Choose an option” screen, and then select Advanced options > Startup Settings > Restart.
  4. Your device will restart and display a list of options. Hit the number “5” or “F5” key on your keyboard to activate Safe Mode with Networking.
  5. Now, try updating your drivers manually via Device Manager. Check if there are devices with the yellow exclamation mark or red X next to them. Right-click on such devices and select “Update driver”. If no updates are available, right-click them and select “Uninstall device”.

After your devices have been uninstalled, restart your PC. Windows will detect the missing devices and automatically reinstall them along with their drivers. You can also check for Windows updates and install any that are available.

The tricky thing about manually updating your drivers is knowing how to do it properly. Although drivers are available on their manufacturers’ websites, you will have to get the right version of each driver. For the average user, this can be a confusing, tedious, and time-consuming task.

The best alternative is to take advantage of driver updating software like Auslogics Driver Updater. Not only will the tool help you eliminate the frustration of dealing with device driver issues, but you’ll also get real-time support from experienced technicians.


Resolve PC Issues with Driver Updater

Unstable PC performance is often caused by outdated or corrupt drivers. Auslogics Driver Updater diagnoses driver issues and lets you update old drivers all at once or one at a time to get your PC running smoother

Auslogics Driver Updater is a product of Auslogics, certified Microsoft® Silver Application Developer

Once installed, Driver Updater performs a quick scan of your operating system and lets you know the device drivers currently installed on your PC and those that are outdated. It will fix all malfunctioning drivers with the click of a button and help to resolve system driver issues on your Windows 10 PC.

Ensuring that your drivers are updated should be part of your regular PC maintenance, and Driver Updater simplifies this task, thanks to the Scheduler function. This option lets you schedule automatic maintenance after predetermined intervals, say every week or fortnight. This keeps your device drivers always updated, ensuring flawless hardware operation.

After you’ve updated all the device drivers, restart your PC and check if it still throws the ‘The operating system cannot be booted because of important system driver errors’ notification.

Roll Back the Problematic Driver

If you’re still getting the error, try rolling the problematic driver back to the previous version. If you used Driver Updater, simply go to the “Restore” tab, select the driver you want to restore, and click on the “Restore” button.

You can also roll back your driver via Device Manager:

  1. Open the “Power User” menu using the Win + X shortcut, and select “Device Manager”.
  2. Expand the category containing the device whose driver you want to roll back, right-click on the device and select “Properties”.
  3. Under the “Driver” tab, click on the “Roll Back Driver” option and then click “OK”.

If this doesn’t work, move on to the next solution below.

Solution 3: Repair Corrupt System Files

Windows comes with various tools to help fix and repair corrupt system files. One such tool is the System File Checker (SFC). To run it, you need to open an elevated Сommand Prompt in Safe Mode and execute a simple command.

Here are the detailed instructions:

  1. Start your computer in Safe Mode as shown above.
  2. Press the Win + R keyboard shortcut and type cmd into the “Run” box. Don’t press “Enter” just yet. Instead, hit the Ctrl + Shift + Enter shortcut to launch the Command Prompt as an administrator.
  3. Now, execute the command sfc /scannow. The process will take a while, and once it has been completed successfully, the system driver errors should be resolved.

Solution 4: Delete the Problematic Driver

If you know the exact device driver causing the ‘The operating system cannot be booted because of important system driver errors’ issue, you can delete it. However, since your system can’t boot normally, you’ll have to complete the task in the Advanced Options environment.

Only use this process if you know what you’re doing and have an idea of which drivers are faulty.

To proceed, follow the steps below:

  1. Turn on the PC. Just as Windows starts loading, hold down the power button until the PC shuts down.
  2. Repeat this process around three times until the recovery window shows up.
  3. On the Choose an option screen, open Troubleshoot > Advanced options and then select Startup Settings > Restart.
  4. Choose option 4 or 5 to enable Safe Mode or Safe Mode with Networking respectively.
  5. Now, open the Command Prompt as an admin and execute the following command:


cd windows\system32

del netqevbda.inf

Once you’re done, delete the qevbd.inf file or any other faulty driver as well.

Solution 5: Repair Your Windows Installation

The Repair process helps to fix problems that are keeping Windows from loading properly. To use this tool, follow our guide below:

  1. If your PC is switched off, press the power button to turn it on. When the PC starts to boot up, hold down the appropriate function key to get into the Recovery Console. The function keys will vary depending on your computer brand. However, the most commonly used function keys are F1, F2, F10, and F12.
  2. If you cannot access the Recovery Console, you’ll need Windows installation media. If you have it, plug the Windows 10 installation DVD or USB flash drive into your PC. You will have to change the boot order in BIOS to boot from the DVD or USB flash drive and then restart your computer to boot to the Windows installation disc.
  3. Choose “Next” in the Windows Setup window and select the “Repair your computer” option in the bottom left corner.
  4. Follow the prompts to finish the process.

The repair process will only attempt to replace the Windows operating system files, leaving your files intact. If performing a Windows repair doesn’t work, you might have to restore your system.

Solution 6: Perform a System Restore

Restoring your system to a state when everything was functioning properly may be your best bet in resolving the system driver errors. For this to work, you must at least have an idea as to when the error first occurred.

To perform a system restore, you will have to boot into Safe Mode or access System Restore in the Windows Recovery Environment (winRE), as shown in solution 2 above. When you get to the “Advanced options” section, choose “System Restore”.

If you booted your PC in Safe Mode, do the following:

  1. Press the Windows logo + S shortcut, type “Restore” (without quotes) and select the option that says “Create a restore point”.
  2. Select “System Restore”, wait a few seconds while Windows prepares itself for the automatic system restore process, and then click on “Next”.
  3. Select a restore point and click “Next”.
  4. Click on “Finish” and let Windows do the rest.

Once the system has been restored, you should no longer have problems booting your operating system. This process will delete or reinstall some programs and applications that you have previously installed or uninstalled. We, therefore, recommend that you note down all the affected programs before you proceed so that you know which ones will require reinstalling or uninstalling.

Solution 7: Reset Windows

If you’re still getting system driver errors after trying all the above solutions, the best course of action is to reset your operating system. To do this, you’ll need installation media. If you don’t have installation media, you can easily create it on another computer:

  1. Simply download the Media Creation Tool and run it.
  2. Choose “Create installation media for another PC”, and select the appropriate language, edition, and architecture (32-bit or 64-bit).
  3. Follow the prompts to finish creating the installation media.

Now follow these steps to reset Windows:

  1. Insert the installation media into your PC and switch it on. But first, be sure to change the boot order so that Windows can boot from the drive.
  2. On the initial setup screen, choose your language and other preferences and select “Next”.
  3. Click on “Repair your computer”, and then select Troubleshoot > Advanced options > System Restore > Reset this PC.

This process will reset Windows 10 and should fix the driver issues preventing Windows from booting normally.

Still need help fixing the “The operating system cannot be booted because of important system driver errors” issue? Talk to us by dropping a comment below.