How to Fix The Stop 0x0000007f Error

What is the "Stop 0x0000007F” or UNEXPECTED_KERNEL_MODE_TRAP Error?

Stop 0x0000007f is an error which occurs when there is a problem with the hardware installed on the system. The hardware problems could include a faulty RAM (Random access Memory), or a Mother board failure or Over clocking system issues.  This is more of a hardware issue and not really a software problem.

Operating Systems affected are:

  • Win XP Home and Professional.
  • Win 2000 Professional, Server, Enterprise, Data centre editions.
  • Win NT Server, Workstation Editions.

Cause of the STOP 0x0000007F error

This error can be caused due to various reasons. Some of these reasons are:

  • RAM Module Failure
  • Mismatched Memory Modules
  • Faulty Motherboard
  • System is Over-clocked for higher performance

Here is how you can deal with each one of them:

RAM Module Failure – RAM is where the data related to the operating system and the hardware is stored. The data is erased when the system shuts down and things are written back into the memory once the system restarts.

When the RAM fails all the important data of the Windows kernel which is to be written on to the RAM fails. This is when you receive the STOP error 0x0000007F for Kernel Mode Trap. The solution to check the memory module is –

  • Try the memory in another slot of the motherboard. If there is another memory in the other slot put one RAM module at a time in both the slots and check for the error.
  • If there is only one memory module you can swap it with another system which has a similar module.
  • If the memory module is faulty, then the other system will also show similar blue screen error or refuse to start.
  • You can run a diagnostic on the RAM module using the diagnostics provided by the manufacturer.

Mismatched Memory Modules – The common speeds of the memory modules are 200, 266, 333 and 400 MHz.  A system can have one memory module of 200 MHz and another module running at a 400 MHz. This mismatch can create problems with the functioning of the system and result in a STOP error. The best way to solve this problem is installing memory modules of the same speed instead of a mix and match.

Faulty Motherboard – Failure of any of the components of the motherboard can cause the KERNEL_MODE_TRAP error. You can disable all the onboard devices to check for this error. Swapping motherboards and running onboard diagnostics can also help solve this issue.

Over clocking of the system – If the system clock speed has been increased to generate faster speeds it can sometimes give the blue screen error. In this case, putting the system back to the original speed will solve the problem.

Rare Issue with Symantec Norton Antivirus

This issue is also related to Symantec Norton Antivirus installed on Windows NT/2000/2003/XP. If your system generates a “Stop 0x0000007F” error upon installation of the antivirus, it can be due to limited kernel space provided for the kernel drivers. This can be solved using a hotfix provided by Microsoft.

You can download the hotfix from the Microsoft Support website page.

Intel Application accelerator also has a similar issue with Norton. This can be resolved using the latest drivers from Intel Application Accelerator page.

If this doesn’t solve the problem you can visit the Symantec Website for further clarifications.

This is a peculiar issue and has to be looked into only if you have Norton Antivirus and Windows 2000 or Windows XP operating system.