Tuesday, June 15, 2010

Fix the classpnp.sys problem, Windows 7 SSD macbook

After I did a lot pressure on CPU performance testing, My windows 7 64 bit [macbook, OCZ SSD, 64 bit ultimate edition]become no responding at all. then I just hold the power key and force a reboot. Sadly enough, it even can’t boot up. Press F8 to try the safemode, no Luck . Get an error like this,  one system driver can’t be loaded. Always, It means the file is corrupt and All you need to fix is find a way to replace the file.


Here is How-to, It is proved to work great on my Macbook win 7 74 bit.

  1. Copy the Classpnp.sys file from another PC to an external hd or USB drive. PLEASE Note, 32 bit /64 bit system differs. Make sure you get the same version as you OS.
  2. Insert one windows DVD to the dvdrom, try boot with the DVD, to setup a New OS (don’t click to go further, all we need is just a command promot that we can copy the file from USB to your Primary HD), For MACbook, Hold and Press “C” to initial the setup.
  3. after the setup GUI is loaded, Run “Shift + F10” to Bring a Command Prompt, this feature has been in the Windows setup GUI since win 2000. So for step 2, inserting any version of windows is fine.


  1. Copy the file from your backup drive to \windows\system32\drivers\classPNP.sys
  2. remove the DVD and external HD, restart the PC
  3. if you get a hint to Repair the PC, forget it. Not make any sense here. until now, all will be fixed.


For more troubleshooting entries.


Anonymous said...

Not working for me still the same problem. Windows 7 still hangs.

Anonymous said...

Ran chkdsk c: /r and then I renamed the older file and copied over a new one from a server with exact same hardware/OS version to a usb. Using xcopy copied over the file to c:\windows\system32\drivers

Avinash said...

You may also want to verify the SATA operation in BIOS. Try changing from AHCI to ATA mode.

Lion said...

yeah i had 4 HDD's hooked up and i was unable to repair,scan,start etc... it would simply hang and reboot after 7-10 minutes even when i tried loading a different partition with another version of windows 7 or xp on it it still crashed leading me to believe it wasn't just a corrupted file. I unplugged all the HDD's except the system drive and once it rebooted system repair finally worked and loaded fine fixing the issue and loading windows fully.

TheAmateur said...

I had this Classpnp issue on a 3 week old Acer Aspire one 522 netbook. Set it to dual boot with linux, and when the problem arose, it woudn't boot to linux either, therefore it was not an issue with any of the windows files. classpnp runs SCSI devices, I believe, so it could well be that a bit of hardware has failed. Unplugging the wifi board gave no joy, and swapping out a known good memory module didn't help, so it's not either of those. The issue can only be that it's lost a BIOS setting, there's a HDD issue, or something on the motherboard. My feeling is that it's a part on the motherboard which is prone to blowing, as the net is crammed with people with dead laptops with this classpnp issue. I simply sent mine back, but my gut feeling is that it's the onboard graphics that is failing. I suspect people are (like me) using them for games, and rather than getting crappy frame rates, or games not running, they're just running hotter than spec and cooking components.

Alpanama said...

Your solution worked for me, thanks a lot. By the way, I used a Windows 2008 x64 R2 classpnp.sys file and I can confirm that it will work.

Alpanama said...

Your solution worked for me, thanks a lot. By the way, I used a Windows 2008 x64 R2 classpnp.sys file and I can confirm that it will work.

qwerty said...
This comment has been removed by the author.
qwerty said...

Hi! i'm having a the same problem. I tried pressing the "Shift+F10" and yes "Administrator X:\windows\system32\cmd.exe" has poped out. Now my problem is I dont know how to copy the file "---\classpnp.sys" & etc. to my HHD. can you help my with my problem?. please show me a step-by-step procedure, i'm just an amateur in computers.

I hope you could help me with this.


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