Long-time Windows users are aware that most Windows errors occur once you've booted the computer. But, some errors may appear during the boot process and after logging in as well.

The "an unexpected I/O error has occurred (0xc00000e9)" is one such error. As its name implies, the error is usually caused by a malfunctioning I/O device, like a keyboard or mouse. A corrupted system file can also cause this error.

Luckily, there are multiple ways to fix this error on your PC:

1. Check the Hardware

The first step you should take when trying to diagnose this error is to ensure that all hardware is properly connected. Check for any damaged ports or loosely connected hardware.

There are multiple ways to check whether the 0xc00000e9 error is caused by a hardware malfunction:

  1. Disconnect all peripherals such as mice, keyboards, speakers, and scanners from your PC. Now, try and boot your computer as you normally would. If the error persists, then a software issue or improper configuration could be the reason.
  2. If you're comfortable dealing with the internal components of your computer, try re-slotting your graphics card, RAM, and storage drive.
  3. If your mouse or keyboard came with companion software, uninstall it and check if the error persists.

2. Update System Drivers

Most errors in Windows can be traced back to an outdated or unstable driver. The unexpected I/O error is no exception. All I/O devices connected to your computer interact with Windows using drivers. So, it's essential to keep these drivers updated.

Related: How to Find and Replace Outdated Windows Drivers

You can manually update these drivers using the Device Manager utility:

Updating drivers using the Device Manager
  1. Press Windows Key + R to launch the Run prompt. Type devmgmt.msc in the prompt and hit Enter to launch the Device Manager.
  2. In the Device Manager window, expand sections related to I/O devices.
  3. Right-click the required device and click on Update driver.
  4. In the Update driver wizard window, click on Search automatically for drivers.
  5. Windows will automatically search the web for the latest device drivers and install them.

While outdated drivers usually cause driver malfunctions, it is also possible that a new driver update has some compatibility issues with Windows.

If the error appeared after you updated the system drivers or downloaded a Windows update, it might be worth your while to roll back those changes and check for the error again.

How to Roll Back Drivers

Roll back drivers in Windows 10
  1. Press Windows Key + R to open the Run prompt. Type devmgmt.msc in the prompt and press Enter to open the Device Manager.
  2. Again, in the Device Manager window, expand all I/O related sections, right-click on the device, and click on Properties.
  3. Under the Driver tab, click on Roll Back Driver.
  4. Click on OK and reboot your computer.

3. Use SFC and CHKDSK to Fix Corrupt System Files

Sometimes, Windows files can get corrupted due to malware or third-party applications. This results in many blue screen errors, including the I/O error in question. Fortunately, there are quite a few in-built utilities that can automatically detect and fix these files.

System File Checker (SFC) and Check Disk (CHKDSK) are two such utilities. SFC scans and repairs any missing or corrupt Windows files, while CHKDSK checks for any disk-related errors on your computer.

Related: What Is the Difference Between CHKDSK, SFC, and DISM in Windows 10

Running both these utilities is the best way to ensure your computer is working in its ideal state.

How to Run SFC

  1. In the Start menu search bar, type cmd, and from the search results, right-click Command Prompt > Run as administrator.
  2. In the Command Prompt window, type sfc /scannow and hit Enter.
  3. The SFC utility will begin scanning your computer. Be patient as the process may take a while.

How to Run CHKDSK

chkdsk utility in Windows
  1. Follow step 1 from the section above to launch Command Prompt as administrator.
  2. In the window, type chkdsk c: /f /r /x and press Enter.
  3. The CHKDSK utility will start scanning and fixing problems on your storage drive.
  4. Close Command Prompt and reboot the computer.

It is important to add the /f /r /x parameters at the end of the chkdsk command because, without them, the utility will just scan for errors but not repair them.

4. Ensure That the Volume Boot Code Is Using BOOTMGR

This is an advanced troubleshooting method that should be used when none of the aforementioned methods work.

Also, use this method only if the I/O error appears during the boot process and you haven't yet reached the login screen.

Sometimes, the Windows volume boot code can become corrupt or associate with another bootloader instead of the default BOOTMGR. This results in many booting errors, including the 0x00000e9 error.

How to Fix the Volume Boot Code and Associate It With BOOTMGR

Making BOOTMGR the default bootloader Windows 10
  1. Boot into the Windows Recovery Environment (WinRE). There are multiple ways to boot into WinRE directly.
  2. If you cannot log in at all, then it may be best to perform a hard reboot: press and hold the Power button until your PC shuts off, press the Power button again, and as soon as the manufacturer's logo appears, press and hold the Power button.
  3. Repeat these steps until you see a blue screen. Here, click on See advanced repair options.
  4. In the Advanced options menu, click on Command Prompt.
  5. In the Command Prompt, type bootsect nt60 /sys and press Enter.
  6. Close the Command Prompt and go back, then click on Restart now.

5. Scan for Malware

If you're using a properly configured Windows Defender or third-party antivirus software, it is unlikely that your computer has been infected by malware.

However, if none of the methods outlined above are helping, it is advisable to scan your computer for malware.

While the process is different for every third-party antivirus solution, in most cases, you can just right-click on the antivirus icon in the system tray and click on Scan.

How to Use Windows Defender to Scan for Malware

Windows Defender full scan.
  1. Click on the Start button and go to Settings > Update & Security > Windows Security.
  2. Under Protection areas, click Virus & threat protection.
  3. Under Current threats, click on Scan options.
  4. Select Full scan and then click on Scan now.
  5. Wait for Windows Defender to scan and remove malware from your computer.
  6. After the scan is complete, restart your computer and see if the error persists.

Error 0xc00000e9 Resolved on Windows 10

Using the procedures outlined above, you can easily resolve the unexpected I/O error without damaging your Windows 10 PC.

Frequent blue screen errors can also be a sign of a failing hard drive. It's better to catch these symptoms early so that you can back up your data.