0x000001AB is a kernel/debugger stop code result. It indicates that an attempt was made to access memory outside of the valid kernel stack range. In particular, this BugCheck indicates that stack unwinding crossed over into an invalid kernel stack. This might indicate that the kernel stack pointer has become corrupted during exception dispatch or unwind (e.g. due to stack corruption of a frame pointer), or that a driver is executing off of a stack that is not a legal kernel stack.
Code reference and safe checks
Read the exact screen and operation before selecting a repair. This page does not run commands or collect files, keys or logs.
What this value means
It indicates that an attempt was made to access memory outside of the valid kernel stack range. In particular, this BugCheck indicates that stack unwinding crossed over into an invalid kernel stack. This might indicate that the kernel stack pointer has become corrupted during exception dispatch or unwind (e.g. due to stack corruption of a frame pointer), or that a driver is executing off of a stack that is not a legal kernel stack.
UNWIND_ON_INVALID_STACK identifies a stop-code family. The four bug-check parameters and dump, if available, help distinguish the actual failure path.
| Code | 0x000001AB |
|---|---|
| Short hex form | 0x1AB |
| Symbol | UNWIND_ON_INVALID_STACK |
| Windows family | Blue screen and stop codes |
| Source level | Microsoft bug-check page |
Microsoft’s technical cause notes add: An attempt to access an invalid stack occurred. As kernel stack is limited in size, the developer needs to be careful with tracking it limits, for example when using it to copy blocks of video memory. For information about the Windows Kernel stack, see Using the Kernel Stack .
Safe next steps
- For 0x000001AB (UNWIND_ON_INVALID_STACK), record the exact stop code and parameters. Microsoft’s debugger reference may describe a kernel condition rather than a consumer fix.
- If crashes repeat, inspect the dump locally with official WinDbg and compare its parameters with this code’s Microsoft page.
- Do not enable Driver Verifier or change firmware as a generic first step; ask qualified support if the PC cannot start.
After one step, repeat the original operation and record whether this same code returns. A different code needs a fresh interpretation.
What this code cannot prove
The source establishes the identifier and reference meaning. It does not establish the cause on your specific PC.
If Windows no longer starts or the issue repeats with hardware warnings, protect files and use manufacturer or qualified support.
Official reference and verification
Source type: Microsoft bug-check page. Checked against the source set on Nov 2, 2026.
The reference gives the meaning of this identifier. It does not inspect your PC or guarantee that one repair will work.