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
This article is for programmers. If you're a customer who has received a blue screen error code while using your computer, see Troubleshoot blue screen errors.
IRQL_UNEXPECTED_VALUE Parameters
| Parameter | Description |
|---|---|
1 |
The value of the following bit computation: (Current IRQL << 16) | (Expected IRQL << 8) | UniqueValue |
2 - Depends on UniqueValue |
If UniqueValue is 0 or 1: APC->KernelRoutine. If UniqueValue is 2: the callout routine If UniqueValue is 3: the interrupt's ServiceRoutine If UniqueValue is 0xfe: 1 if APCs are disabled |
3- Depends on UniqueValue |
If UniqueValue is 0 or 1: APC If UniqueValue is 2: the callout's parameter If UniqueValue is 3: KINTERRUPT |
4 - Depends on UniqueValue |
If UniqueValue is 0 or 1: APC->NormalRoutine |
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.
The !analyze debug extension displays information about the bug check and can be very helpful in determining the root cause.