Common Stop Codes

Windows NT employs about 150 Stop Codes. However,you encounter the following Stop Codes most frequently. For a complete list ofNT's Stop Codes, see the bugcodes.h file in the Windows NT Device Driver Kit.

IRQL_NOT_LESS_OR_EQUAL 0x0A
This code is probably the most frequently appearing code, and it usuallyresults from a buggy driver. The most common source of the problem is that theVirtual Memory Manager has detected a kernel-mode component's attempt to accesspageable memory when the IRQL is Dispatch Level or higher and the memory is inthe paging file. The IRQL must be below Dispatch Level for this operation to belegal. Look at the modules listed in the Stop Code and stack trace areas of thescreen for a possible candidate. This code can also be a side effect resultingfrom a driver not shown in either area that scribbled on memory it shouldn'thave.

UNEXPECTED_KERNEL_MODE_TRAP 0x7F and KMODE_EXCEPTION_NOT_HANDLED 0x1E
These two codes also show up frequently. In this case, the Microkernel'sprocessor exception handler has detected that a driver or subsystem has tried toexecute an illegal processor instruction, or a software instruction that NTcannot interpret. The cause can be a faulty memory module or a driver that hascorrupted memory. The module information on the blue screen is usuallymisleading in this case, making it difficult to identify the source of theproblem.

NO_MORE_IRP_STACK_LOCATIONS 0x35
With this code, if you've added a new virus scanner or someone has accesseda shared volume over the network for the first time on the machine, the Serverdevice driver can be at fault. The Server device driver constructs I/O requestpackets with a slot for every device driver on the path to the disk. Sometimesthe number of I/O request packets the Server device driver allocates isinsufficient, resulting in this Stop Code. Try increasing the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesLanmanServerIrpStackSize setting to a number higher than 4 (or whatever it'sset to) and see whether the problem goes away.

INACCESSIBLE_BOOT_DEVICE 0x7B
If you see this Stop Code, NT is very early in a boot and cannot access thedisk partition that boot.ini is pointing to for the location of the system files(where your winnt directory resides). The disk containing that partition isfaulty, or the data on the disk or partition has become corrupt. I encounteredthis code when I left an NT 4.0 distribution CD-ROM in my CD-ROM drive andrebooted. The computer tried to boot from the CD-ROM, and NT displayed thismessage when it couldn't continue. An NT repair install is worth a try, butyou'll likely have to buy a new driver or reformat, reinstall, and restorebacked-up data.