The Stop 0x7F message indicates that one of two types of problems occurred in kernel-mode:
• A condition that the kernel is not allowed to have or intercept (also known as a bound trap).
• A fault occurred while processing an earlier fault (also known as a double fault).
Interpreting the Stop 0x7F Message
This Stop message has four parameters, as listed below.
Parameters for the Stop 0x7F Message
Parameter Description
Parameter 1 Processor exception code.
Parameter 2 This value is 0x00000000 (zero).
Parameter 3 This value is 0x00000000 (zero).
Parameter 4 This value is 0x00000000 (zero).
Parameter 1 is the most important parameter and can have several different values, indicating different causes of this error. You can find all conditions that cause a Stop 0x7F in any x86 microprocessor reference manual because they are specific to the x86 platform.
Common Exception Codes for the Stop 0x7F Message
Exception Code Description
0x00000000:
Divide by Zero Error Occurs when a divide (DIV) instruction is run in a kernel process and the divisor is 0. Memory corruption, other hardware failures, or software problems can cause this error message.
0x00000004:
Overflow Occurs when the processor carries out a call to an interrupt handler when the overflow (OF) flag is set.
0x00000005:
Bounds Check Fault Indicates that the processor, while carrying out a BOUND instruction, found that the operand exceeded the specified limits. BOUND instructions ensure that a signed array index is within a certain range.
0x00000006:
Invalid Opcode Generated when the processor attempts to run an invalid instruction. This typically occurs when a hardware memory problem corrupts the instruction pointer, which then points to a wrong location.
0x00000008:
Double Fault Indicates an exception while trying to call the handler for a prior exception. Usually, a processor can handle two exceptions serially, but certain exceptions (almost always caused by hardware problems) cause the processor to signal a double fault.
Less common codes are listed below:
Less Common Exception Codes for the Stop 0x7F Message
Exception Code Description
0x00000001 A system-debugger call
0x00000003 A debugger breakpoint
0x0000000A A corrupted Task State Segment
0x0000000B An access to a memory segment that was not present
0x0000000C An access to memory beyond the limits of a stack
0x0000000D An exception not covered by some other exception; a protection fault that pertains to access violations for applications
Troubleshooting the Stop 0x7F Error
The following sections list the most common sources for this Stop error and suggest some troubleshooting solutions.
Memory hardware issues
Stop 0x7F messages are typically caused by defective, malfunctioning, or failed memory hardware. If you added new hardware recently, remove and replace it to determine if it is causing or contributing to the problem. Run diagnostics software supplied by the system manufacturer to determine if the component has failed.
Processor hardware issues
This Stop error can occur when the processor or the processor cache are failing; if this is the case, replacing the processor will resolve the problem. Running the processor (or other components) beyond the rated specification, known as “overclocking,” can cause Stop 0x7F or other error messages due to heat buildup. When diagnosing problems on overclocked systems, first restore all clock and bus speed settings to the manufacturer-recommended values to determine if this resolves the issues.
Motherboard issues
The problem might also be caused by cracks, scratched traces, or defective components on the motherboard. If all else fails, take the system motherboard to a repair facility for diagnostic testing.
Software incompatibility issues
Stop 0x7F messages can occur after you install incompatible applications, drivers, or system services. Contact the software manufacturer about possible Windows Server 2003–specific updates. Using updated software is especially important for backup programs, multimedia applications, antivirus scanners, and CD/DVD mastering tools.
