STOP 0x0000007F on Pentium Pro Systems Running Windows NT 3.51

• Microsoft Windows NT Workstation version 3.51
• Microsoft Windows NT Server version 3.51

SYMPTOMS

Pentium Pro systems running Windows NT 3.51 and using Halmps.dll, which is the Hardware Abstraction Layer DLL for most Intel multiprocessor systems, or Halapic.dll, the uniprocessor version of the same HAL, may experience repeated STOP 0x0000007F (UNEXPECTED_KERNEL_MODE_TRAP) errors.

CAUSE

Hardware interrupts are not being disabled at the appropriate time, resulting in the possibility of a stack fault, given the timing characteristics of the Pentium Pro processor.

NOTE: The same STOP code may also result from other causes, so the fix mentioned here will not resolve all instances of this problem. For more information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE: Q137539
   TITLE  : "General Causes of STOP 0x0000007F."

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.51. This problem was corrected in the latest Windows NT 3.51 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K