classpnp.sys error

Fix classpnp.sys Hang Error in Windows

What is classpnp.sys?

It is a digitally signed Microsoft Windows Operating System file for SCSI class which is an acronym for Small Computer System Interface.

Location of classpnp.sys

This file can be found residing under the System Root directory –


classpnp.sys freezes under SAFE MODE

You must have encountered this error after you have updated your Windows version and now you are unable to log into your system. This is usually due to incompatible drivers which are not updated to work with the latest version of Windows. Being unable to communicate with the hardware peripherals during the boot process, the operating system hangs. This problem is most common while upgrading from Windows Xp to Windows Vista.

How to stop classpnp.sys from loading?

You cannot stop this file from loading directly to your system. This is a core system process and cannot be stopped explicitly from being directly called on for the boot process. It is utmost advisable not to modify this file cause doing so might make your system unstable.

Fix and Repair classpnp.sys

Follow these steps to fix the classpnp.sys error by modifying the BIOS settings:

classpnp.sys error

  1. Restart your laptop/desktop
  2. Press F12 to access the BIOS panel
  3. Find and select “Advanced” menu
  4. Now select “System Config”
  5. Find SATA Controller and change it from “AHCI” to “Compatibility”
  6. Now Press F10 and then “Y” to Exit the saved configuration

Download classpnp.sys

As I have always said that downloading a system file from third party website is a complete unsafe application. There is however no official source available as well. So, if you have no other option we would advice you to borrow this file from someone who has the same laptop model or similar hardware configuration. Save it on a disk/USB drive. And then copy it to the above mentioned file location.