ntdll.dll error usually appears when there is an unknow hard disc drive error, and you may find difficult to complete any task on your computer.

Common ntdll. dll error messages
- "STOP: C0000221 Unknown Hard Error \SystemRoot\System32\ntdll.dll"
- "STOP: C0000221 unknown hard error Path\File_name"
- "STOP: 0xC0000221 unknown hard errorC:\Winnt\System32\Ntdll.dll (or another specific file or driver)"
- "XVIDCORE.DLL not found. Reinstalling might help fix this."
- "STOP: 0xC0000221 STATUS_IMAGE_CHECKSUM_MISMATCHPath\File_name"

How to install ntdll.dll file?

1. Press Start and select Run
2. Type CMD and press Enter (or if you use Windows ME, type COMMAND)
3. Type regsvr32 ntdll.dll and press Enter
4. In the end, you should receive a message saying that your file was successfully installed or uninstalled.