- Software and digital services
- Operating system
CRITICAL_STRUCTURE_CORRUPTION
Windows CRITICAL_STRUCTURE_CORRUPTION: kernel data corrupted
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
CRITICAL_STRUCTURE_CORRUPTION (0x109) means Windows detected critical kernel code or data that was modified or corrupted. First step: if the message names a driver, disable it or get its update from the maker.
Safety first
Stop and check this first
- Copy your documents to an external drive or the cloud before uninstalling drivers, restoring or resetting Windows.
- Do not install programs that promise to modify the Windows kernel: 64-bit Windows only accepts patches authorised by Microsoft.
Safe checks you can perform
- Driver named in the message or the log
- Memory diagnostic from Control Panel
- Remove recently added hardware
- PC maker hardware diagnostics
Leave these tasks to a qualified professional
- Do not attempt this professional task: Dump analysis with !analyze and the stack
- Do not attempt this professional task: Driver check with Driver Verifier
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Dump analysis with !analyze and the stack
What they doThe technician loads the dump in WinDbg, runs !analyze -v, reviews the stack on each processor and reads the fourth parameter to learn which kernel region was altered.
They must show youthe !analyze -v output, the type of corrupted region and the driver involved.
In writingthe responsible driver or component and the fix applied.
Driver check with Driver Verifier
What they doIf the dumps point to nothing clear, the technician enables Driver Verifier on suspect drivers, in small groups, to make the culprit reveal itself.
They must show youwhich drivers were verified and the dump the failure produced.
In writingthe driver detected and that Driver Verifier was turned off afterwards.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Driver named in the message or the log
- Who:
- you.
- How:
- note whether the blue screen names a .sys file; then open Event Viewer, Windows Logs, System, and look for error messages close to the stop.
- Result that matters:
- identifying a specific driver to disable or update.
- If a driver is named:
- get the latest version from the maker's website or disable the device until you have it.
- If none is named:
- continue with the memory test and leave the dump to the technician.
- Evidence to keep:
- name of the .sys file and a screenshot of the System event.
Evidence: Stop code error or bug check troubleshooting (IT professionals) · Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
Memory diagnostic from Control Panel
- Who:
- you.
- How:
- type Memory in the Control Panel search box and select Diagnose your computer's memory problems; when it ends, open Event Viewer, System log, and find the MemoryDiagnostics-Results entry.
- Result that matters:
- reading the RAM test result Windows writes to the log.
- If the entry reports errors:
- stop using the PC for important work and ask for a hardware test.
- If there are no errors:
- a driver remains the most likely cause.
- Evidence to keep:
- dated screenshot of the MemoryDiagnostics-Results result.
Evidence: Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
Remove recently added hardware
- Who:
- you, after shutting the computer down.
- How:
- disconnect external devices you installed just before the crashes began and start again; check on the maker's website that they support your Windows version.
- Result that matters:
- seeing whether 0x109 goes away without that device.
- If it goes away:
- the device or its driver does not fit your Windows; ask the maker before reconnecting it.
- If nothing changes:
- reconnect it and move on to the PC maker's tests.
- Evidence to keep:
- list of what you removed and the result of each startup.
Evidence: Troubleshooting Windows unexpected restarts and stop code errors · Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
PC maker hardware diagnostics
- Who:
- you.
- How:
- find your computer maker's hardware diagnostic tool on its website and run the full test following its instructions.
- Result that matters:
- getting a maker report on memory, drive and motherboard.
- If the report flags a component:
- keep the error code and contact the maker's support.
- If everything passes:
- the next step is analysing the memory dump.
- Evidence to keep:
- report or result code from the maker's tool.
Evidence: Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Software and digital services
- Brand
- Microsoft Windows
- Product type
- Operating system
Known code variants
- 0x00000109
- 0x109
- blue screen CRITICAL_STRUCTURE_CORRUPTION
- código de detención CRITICAL_STRUCTURE_CORRUPTION
- CRITICAL STRUCTURE CORRUPTION
- pantalla azul CRITICAL_STRUCTURE_CORRUPTION
- STOP 0x00000109
- stop code CRITICAL_STRUCTURE_CORRUPTION
What it means
According to Microsoft, code 0x00000109 appears when the kernel finds that its own critical code or data has changed. The fourth parameter gives the type of region affected, such as a processor table, a function or a process list. 64-bit versions of Windows do not allow the kernel to be patched except through hot patches authorised by Microsoft. Usual causes are a driver modifying the kernel, a debugger attached the wrong way or failing memory. On its own, the code does not show that RAM or any other part is faulty.
Warnings and stop conditions
- Mediumsource verified
Copy your documents to an external drive or the cloud before uninstalling drivers, restoring or resetting Windows.
Evidence: Troubleshooting Windows unexpected restarts and stop code errors
- Mediumsource verified
Do not install programs that promise to modify the Windows kernel: 64-bit Windows only accepts patches authorised by Microsoft.
Evidence: Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
Symptoms and causes
Probable causes · in order
- A driver modifying the kernelCommon
Microsoft lists as the first cause a driver that, by accident or on purpose, changes critical kernel code or data, which 64-bit Windows does not allow.
Evidence: Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
- Memory holding the kernel failingPossible
The official page mentions hardware corruption, for example kernel code or data stored in memory that failed.
Evidence: Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
- Kernel debugger used without attaching it at bootLess common
This happens on development machines when a normal breakpoint is set with a debugger that was not attached when the system started.
Evidence: Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
- Recently fitted part that does not suit your WindowsPossible
Microsoft recommends confirming that any recently installed hardware is compatible with the Windows version on the PC.
Evidence: Troubleshooting Windows unexpected restarts and stop code errors · Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
Virtual technician
Does CRITICAL_STRUCTURE_CORRUPTION still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Stop code error or bug check troubleshooting (IT professionals)
Microsoft · 2026 · official_doc
- 2
Troubleshooting Windows unexpected restarts and stop code errors
Microsoft · 2026 · official_doc
- 3
Solución de problemas de reinicios inesperados y errores de código de detención de Windows
Microsoft · 2026 · official_doc
- 4
Bug Check 0x109 CRITICAL_STRUCTURE_CORRUPTION
Microsoft · 2026 · official_doc
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