What is ntoskrnl.exe?

Ntoskrnl.exe is NT Kernel & System.

This file is part of Microsoft® Windows® Operating System. Ntoskrnl is developed by Microsoft Corporation. It’s a system and hidden file. This file is usually located in the %SYSTEM% folder and its usual size is 3,919,952 bytes.

Ntoskrnl.exe is the kernel image for the Microsoft Windows NT operating systems family. It provides the Kernel and Executive layers of the Windows NT kernel space and is responsible for system services, such as hardware virtualization, process management, and memory management. Among other things, it contains the Cache Manager, the Memory Manager, the Executive, the Kernel, the Security Reference Monitor, and the Scheduler. Ntoskrnl.exe is a critical process in the boot-up cycle and is fundamental for the system operation. It should never appear in WinTasks under normal circumstances.

Important: ntoskrnl can be altered by malware. Scan your computer with Auslogics Anti-Malware to make sure it's not infected.

What to Do When Ntoskrnl.exe Is Missing or Corrupt

Sometimes you can get an error stating that Windows could not start because the Ntoskrnl.exe is missing or corrupt. This error can be caused by a number of things:

1. Keyboard issue
2. Corrupted boot.ini file
3. Missing boot.ini file
4. Missing or corrupted ntoskrnl.exe file
5. Corrupted hard drive or severely corrupted Windows

Here are some tips that might help you solve the problem.

Before applying any fixes mentioned below, try to load the last known good system configuration. To do that, reboot your computer and repeatedly press F8 on boot. It should bring up the Windows Advanced Options Menu. Select Last Known Good Configuration and press Enter.

Keyboard issue

A damaged keyboard cable could be the cause of ntoskrnl.exe error. You can check whether your keyboard is causing the error by replacing it or simply disconnecting it from your computer.

Corrupted boot.ini file

This can happen when the boot.ini file is missing or is configured incorrectly and usually happens after a user has added or removed an operating system or added/removed hard drives.

Make sure that the path to the operating system and its drive/partition is properly configured in the [boot loader] and [operating systems] sections.

Missing boot.ini file

If you are a Windows XP user and your boot.ini is badly corrupted or even missing, you can rebuild the boot.ini file. This Microsoft article describes how to do it.

To restore the original boot.ini file in Microsoft Windows NT or Windows 2000 you will need an ERD (Emergency Repair Disk). Here’s how to use it:

1. Boot the computer with your three Windows NT setup diskettes or the Windows 2000 setup disk.
2. In the setup menu, type R to start the repair.
3. When prompted for the ERD diskette, insert it and inspect the startup environment.

Missing or corrupt ntoskrnl.exe file

This error can also occur if the ntoskrnl.exe file becomes corrupted or is missing. Follow the steps below to restore ntoskrnl.exe:

1. Insert your Microsoft Windows XP CD. This has to be the original XP CD - a recovery CD might not do the trick.
2. Reboot your computer. Press any key when prompted to boot from the CD.
3. When you enter the Windows XP setup menu, press R to enter the recovery console.
4. Select the operating system you wish to fix, and then enter the administrator password.
5. Type expand d:\i386\ntoskrnl.ex_ c:\windows\system32
6. You will be asked whether you want to overwrite the file. Type Y and press Enter to overwrite the ntoskrnl.exe file.
7. Type exit to reboot your computer.

Corrupted hard disk drive or severely corrupted Windows

If you think that your hard drive is responsible for the ntoskrnl.exe error, try running the Check Disk (CHKDSK) tool. Here’s how to use it:

1. Insert the Microsoft Windows XP CD.
2. Reboot your computer. Press any key when prompted to boot from the CD.
3. When you enter the Windows XP setup menu, press R to enter the recovery console.
4. Select the operating system you wish to fix, and then enter the administrator password.
5. When you’ve entered the recovery console, type chkdsk /r
6. Once completed, type exit and see if the problem is solved.

If after trying all of the steps above the ntoskrnl.exe error still occurs, it's likely that Windows is severely corrupted and you need to reinstall the operating system.

If you encounter any errors during the Windows installation, most likely it's hard drive failure and you need a new hard drive.