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Exception Solutions
     
 

Illegal instruction exception

Fatal exception 0xC000001D

 
  Description  
 
       
fatal  
 

An attempt was made to execute an illegal instruction.

The processor initiates this exception when it encounters an invalid instruction. It occurs when program memory is corrupted by software, hardware or an invalid jump is made. Usually this is caused by a serious (but difficult to find) bug in a program.  It can also be caused by a range of hardware problems such as bad bits in memory or the CPU itself.

The file indicated as the source of the problem may have nothing to do with the issue.  A bug in other running software or Windows itself can corrupt memory or the stack such that the fault doesn't occur until the later identified program encounters it.

 
 
 
   
  Key Facts  
     
 
         
Raw Title
  STATUS_ILLEGAL_INSTRUCTION

 
OS
  Windows

occurance meter
 
Type
  Fatal 

   
Vendor
  Microsoft Corporation*

* Reporting vendor, unclear who is responsible for the issue.
   
 
   
  Solutions and Fixes  
     
 
  date Votes Ratings
Replace the Processor
6
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The processor (CPU) may be defective and needs to be replaced. Before taking this step, check if any of these more common issues are occurring that will cause the processor to fail:

  • Confirm both the CPU and system fans are working properly
  • The CPU is properly seated in it's socket and the clamps are in place
  • There is sufficient thermal compound between the CPU and the CPU heatsink
  • The CPU is not being overclocked (via BIOS motherboard settings

If you do replace the CPU with a different model (higher speed or more cores) confirm the power (watts) is the same or lower than the current CPU, or ensure you add additional cooling for the hotter part.

 
   
 
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  FaultWire Staff
Posted: 19-Jan-2009
 
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Check Memory
8
    Add    Flag
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You may have a defective memory. This is even more likely if it only occurs when the system is cold or hot, but not all the time. Use a memory tester to confirm if it is defective or if you have spare memory, try replacement.

Windows 7 and Vista include a Memory Test program when booting from the Windows Installation DVD. Step-by-step instructions with screen shots are available at Using System Restore on 7/Vista/2008 as part of System Recovery.

Several software products that also provide memory and video diagnostics includes Fix-It Utilities Professional and SystemSuite Professional. Other diagnostic products include Eurosoft's PC Check and Iolo's System Mechanic.

Additional Memory Solutions:

  • Confirm all the memory is of the same type and speed. Many motherboards only work correctly when the memory is installed with matched sets and matched speeds.
  • If you added or changed your memory just before this problem occurred, try reverting to the prior memory configuration to confirm it's the source of the problem.
  • Check that the memory is fully seated in the sockets. Memory sockets often have side latches that need to be upright to indicate the memory is correctly locked in place.
  • Confirm the memory resides in the correct slots on the motherboard. You'll need to refer to the motherboard manual to confirm this. There is little consistency, even within a single vendor. Some systems require that memory is installed as matched pairs, but not always adjacent to each other!
  • It's also possible the memory problem is on the video card, as they often contain additional memory. The video card should be tested and/or try a different video card to see if the problem goes away.
 
   
 
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  FaultWire Staff
Posted: 5-Oct-2008
 
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Undo the Last Change
7
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If the system had been working fine, but the problem started to occur right after some change such as installation of new application, driver or hardware, try reverting the system to the prior state to see if the problem goes away. 

For removal of an application
Windows 8:

  1. Press the Windows key and X at the same time. Select Control Panel, then Programs and Features.
  2. Select the software to uninstall and select Uninstall.  Note that the "Uninstall" option does not appear until you click on a program.

Windows 7:

  1. Click on Start, Control Panel, then under Programs, select Uninstall a program.
  2. Select the software to uninstall and select Uninstall.  Note that the "Uninstall" option does not appear until you click on a program.

Windows Vista:

  1. Click on Start, Control Panel, then Programs and Features.
  2. Select the software to uninstall and select Uninstall.

Windows XP:

  1. Click on Start, Control Panel, then Add or Remove Programs.
  2. Select the software to uninstall and select Remove.

 

To disable a driver:

  1. Bring up the system information dialog:

    Windows 8:
    Press the Windows key and X at the same time. Select System.

    Windows 7/Vista/XP:
    On the keyboard, press the Windows key + Pause/Break.

    • or

    Select Start, right click Computer and on the drop-down, select Properties.

     

  2. Click on the left side option Advanced system settings (Windows 8/7/Vista only).
  3. In System Properties, select the Hardware tab, then click on Device Manager button.
  4. Find the hardware/driver of interest (you may need to expand a choice at the "plus" graphic) and double click the choice.
  5. Select the Driver tab. Here you can perform a number of actions such as update the driver, roll Back the driver to an older version, disable or uninstall the driver.
  6. Click OK to exit, then close the Device Manager and other previously opened dialogs.
 
   
 
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  FaultWire Staff
Posted: 5-Oct-2008
 
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Reported Exceptions

You may find more information for this issue in our specific exception reports.

View exception reports for 0xC000001D.
 
   
  Technical Details  
     
 
  technical details

The processor interrupt 6, Invalid Opcode was issued.

Looking at a memory dump, the offset of the issue shown may appear to be a perfectly fine instruction. If this is the case, there are several possibilities:

  • Bad code or a corrupted stack caused program execution to jump into the middle of a multi-byte instruction.
  • Memory bits are not stable and different reads return inconsistent bit values.
 
   
  Vendor Summary  
     
 
Vendor
  Microsoft Corporation (more info...)

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  Notes  
     
  Although less informative than our notes here, you can view the Microsoft MSDN source document for a list of the NTSTATUS codes used when Microsoft encounter a problem with an application.  
     
  While we believe this information up to date and accurate, FAQware is not responsible for any inaccuracies. If you find something that is out of date or inaccurate, please let us know at so we can correct it.