Windows 7 boot stalls at classpnp.sys

Interesting.  Did some more digging.  Turns out that while everyone seems to think the boot is stalling at classpnp.sys, it is in fact stalling at the NEXT file in the boot sequence, which is cdrom.sys (in my case, anyway).  That makes a bit of sense.  In my case, there was a DVD drive while I installed and configured.  It was in a docking base.  In normal use, there is no dvd drive (it is a Thinkpad, which has no internal drive), and if I configure a boot log, the system reports that cdrom.sys did NOT load.

Given the fact that when it failed to boot the repair option claimed that the boot failed because a resource was not available, perhaps the BIOS was reporting a cdrom was available but the system could not find it?  

But I'm just guessing.  I wish that Microsoft would weigh in on this one.  It has been going on for a long time if you Google for it.  

Paul

OK _ I ran into this problem today. Apparently classpnp.sys is a Microsofts SCSI driver but the problem was to actually get to the root cause of this problem I had to turn off automatic reboot on system hang in the F8 startup options. Nothing else I tried geve me a reasonable lead to an answer. I could not get into safe mode, but I could try startup repair but this didn't help as the problem is a hardware driver, not software.

Eventually after turning off automatic reboot I got a BSD which at least pointed to the driver for my Atto Celerity Fibre card being the culprit. Removing this card allowed the system to boot normally. Either the card or driver is corrupt but ... at least I have a place to start.

In my opinion this insane urge to "hide" problems from the user has led to this being one of the most difficult problems to track down, even for a savvy computer user like myself. Microsoft need to develop a reporting system tha tinforms hte user exactly where hardware problems lie - in htis case a log of the failing driver that popped up on the next boot would have been sufficient to identify the problem hardware. So simple and yet so obtuse - Microsoft hit yourself over the head with a 2x4 at least 10 times until the message gets through - abstraction layers are no good when problems are involved.

I'm pretty sure what is happening is that classpnp.sys actually loads any third party SCSI drivers like raid cards, fibre cards, legacy CD drives etc - that is what makes this a difficult problem to track down. Could be a failing hard drive, a dead CD ROM controller or a problem raid card etc

Got the same problem!

No recovery points of my windows can be found from the recovery process.

CHKDSK doesn't work as usual. (Failed to transfer logged messages to the event log with status 50.)

And done all the options from F8 menu.

         <--------------- Problem solved after all the digging --------------->

Update: I got my problem fixed by going in to my Bios and switch from AHCI to IDE. Windows can just boot successfully, and I even skip the whole repair windows process with the windows setup disk after I reset the Bios. Yes, the result came as my digging: My windows 7 came back alive. According to the search I found that people are fixing their classpnp problem by doing the same thing or the other way around. (IDE to AHCI)  But in my case, I was accidently switch the hard drive setting in Bios to AHCI when I flash the customized Bios, and that's why. But I got it fixed by switching AHCI back to IDE.

Give it a try if you have the same problem. Good luck.

Thomas

While in the Safe Mode click the Start button and then click Restart.  It will restart in the normal operating mode.

Yes......  And the point is?

Paul

While in the Safe Mode click the Start button and then click Restart.  It will restart in the normal operating mode.