Bug Check 0xC8: IRQL_UNEXPECTED_VALUE
The IRQL_UNEXPECTED_VALUE bug check has a value of 0x000000C8. This indicates that the processor's IRQL is not what it should be at this time.
Important Info If You Have Received a STOP Code
If you received a blue screen error, or stop code, the computer has shut down abruptly to protect itself from data loss. A hardware device, its driver, or related software might have caused this error. If your copy of Windows came with your computer, call the manufacturer of your computer. If you purchased Windows separately from your computer, Microsoft provides support. To find contact info for Microsoft or your computer manufacturer, Contact Support.
If you have experience with computers and want to try to recover from this error, follow the steps provided in the Microsoft article Resolving STOP (Blue Screen) Errors in Windows.
These actions might prevent an error like this from happening again:
- Download and install updates and device drivers for your computer from Windows Update.
- Scan your computer for computer viruses.
- Check your hard disk for errors.
IRQL_UNEXPECTED_VALUE Parameters
The following parameters are displayed on the blue screen.
| Parameter | Description |
|---|---|
|
1 |
The value of the following bit computation: (Current IRQL << 16) | (Expected IRQL << 8) | UniqueValue |
|
2 |
Zero, or APC->KernelRoutine |
|
3 |
Zero, or APC |
|
4 |
Zero, or APC->NormalRoutine |
You can determine "UniqueValue" by computing (Parameter 1 AND 0xFF). If "UniqueValue" is either zero or one, Parameter 2, Parameter 3, and Parameter 4 will equal the indicated APC pointers. Otherwise, these parameters will equal zero.
Cause
This error is usually caused by a device driver or another lower-level program that changed the IRQL for some period and did not restore the original IRQL at the end of that period. For example, the routine may have acquired a spin lock and failed to release it.
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Build date: 4/9/2013
