Repair Missing or Corrupt Files

If you experience a problem on Windows NT such as a missing or corrupt crucial file, you might find the Microsoft Windows NT Server 4.0 Resource Kit's Repair utility useful. This utility uses an Emergency Repair Disk (ERD) to repair NT installations. If you don't have an ERD, the Repair utility can also use the \repair folder to restore a system. The utility scans a system's disks, finds the NT installations, and locates the \repair folder under the \%systemroot% folder.

Because you can install NT in any folder, you might wonder how the Repair utility determines whether a folder includes an NT installation. To locate an NT installation, the utility searches a system's folders for the microkernel file ntoskrnl.exe.

If the file ntoskrnl.exe is missing, the Repair utility can't find the NT installation. However, if you have a FAT boot partition, you can work around this problem. Boot the system from a DOS or Windows 9x system disk. (Alternatively, you can boot from a second NT installation.) Use the Cd command to change the current directory to the NT folder. Then, navigate to the system32 folder. Create an ordinary file called ntoskrnl.exe. To create this file, go to the command prompt and enter

C:\>copy con ntoskrnl.exe

Then, press F6. Finally, run the Repair utility again. The utility will locate ntoskrnl.exe, determine that the file is corrupt, and replace the file, along with any other missing or corrupt files.

In Windows 2000, Windows File Protection (WFP) monitors ntoskrnl.exe and other crucial files. WFP replaces missing or corrupt files with files from the file cache in realtime, thus avoiding the need for a repair process. In addition, Win2K's Recovery Console gives you read/write capability from a command prompt, even on NTFS partitions.

—Murat Yildirimoglu
murat@yildirimoglu.com