Windows BSOD Error 0x000000C9 — DRIVER_VERIFIER_IOMANAGER_VIOLATION Fix

What Does This Error Mean?

The 0x000000C9 blue screen is called DRIVER_VERIFIER_IOMANAGER_VIOLATION. It means Windows' Driver Verifier tool caught a driver violating the rules of the I/O Manager — the part of Windows that handles reading and writing data to devices. This crash is usually intentional: it means Driver Verifier is working correctly and found a bad driver. The goal is to identify and fix or replace that driver.

Affected Models

Windows 10
Windows 11
Windows 8.1
Windows Server

Common Causes

Driver Verifier is enabled and caught a driver misusing I/O request packets (IRPs)
A driver completed an I/O request twice, or cancelled one that was already completed
A driver passed invalid parameters to an I/O Manager function
A recently installed driver has a bug in how it handles disk, network, or USB read/write operations
A driver freed an IRP while the I/O request was still in progress

How to Fix It

Check if Driver Verifier is enabled on your system. Open Command Prompt as Administrator and type: verifier /query — If it reports active settings, Driver Verifier is running and caused this crash intentionally.

Driver Verifier is a diagnostic tool. If someone enabled it previously to troubleshoot and forgot to disable it, it will keep triggering crashes.
Disable Driver Verifier if you are done troubleshooting. In Administrator Command Prompt type: verifier /reset — then restart. This stops the intentional crashes.

Only disable it if you have already identified the problem driver. If you are still investigating, keep it enabled.
Read the crash dump to find which driver was named. Use the free WhoCrashed tool or open Event Viewer > Windows Logs > System and look for critical errors at the time of the crash.

The driver name is typically a .sys file such as nvlddmkm.sys (NVIDIA) or usbhub.sys (USB). This name tells you which program or device to focus on.
Update or uninstall the driver named in the crash. If it is a GPU driver, download the latest version from NVIDIA, AMD, or Intel's website. If it is a USB or storage driver, check the device manufacturer's support page.

If no update is available, try uninstalling the driver and letting Windows reinstall it automatically on next boot.
Run DISM /Online /Cleanup-Image /RestoreHealth in Administrator Command Prompt to repair Windows component files. Restart afterward and monitor for further crashes.

If the flagged driver is a built-in Windows driver, DISM can replace it with a clean copy from Microsoft's servers.

When to Call a Professional

Once Driver Verifier identifies the problem driver by name, search online for that driver file name to identify which program or device it belongs to. If the driver is from a hardware manufacturer, contact them for an updated version. If the driver is part of Windows itself and is flagged, run DISM repair and consider a Windows repair install. A technician can help interpret the crash dump if you cannot identify the driver on your own.

Frequently Asked Questions

What is an IRP and why do drivers need to handle them correctly?

An IRP (I/O Request Packet) is how Windows passes read, write, and control instructions to device drivers. Think of it like a work order handed to a driver. The driver must process it once and mark it complete — exactly once. If a driver marks it complete twice, or abandons it mid-process, the I/O Manager detects the violation. These rules prevent data corruption and system instability.

Did I accidentally turn on Driver Verifier?

It is possible. Driver Verifier can be enabled by diagnostic tools, PC optimization software, or even some games or apps that install kernel drivers. If you never intentionally enabled it, run: verifier /query in Command Prompt to check. If it is active, disable it with: verifier /reset and restart. Your crashes should stop if Verifier was the cause.

Is this error dangerous for my data?

The crashes themselves are not likely to corrupt your data because Windows shuts down cleanly when Driver Verifier triggers. However, if the underlying driver bug is causing actual I/O corruption — meaning incorrect data being written to your drive — that is a risk. Run CHKDSK from Command Prompt to check your drive for errors: chkdsk C: /f /r — and schedule it to run on the next restart.