| Previous | Next |
| ERROR_ACCESS_DISABLED_BY_POLICY | ERROR_CSCSHARE_OFFLINE |
ERROR_REG_NAT_CONSUMPTION
An Itanium register carried an invalid NaT state into execution.
ERROR_REG_NAT_CONSUMPTION is Win32 error 1261 (0x4ED). Microsoft defines it as Itanium-specific: a program attempted to use an invalid register value, commonly because the register was not initialized. NaT means “Not a Thing,” an architectural marker used by Itanium speculative execution.
Modern interpretation
Itanium Windows systems are legacy. On a current x64 or ARM64 machine, a live operating-system return of 1261 is unusual. First verify that the value was not read from an old crash report, translated incorrectly from another status space, truncated from an HRESULT, or supplied by application-defined code that reused the same integer.
Evidence for a genuine legacy failure
- processor architecture and exact Windows build
- faulting instruction address, module, and symbol information
- register state and exception record from the original dump
- compiler version, optimization settings, and generated image machine type
- the data-flow path that should have initialized the consumed register
Diagnostic sequence
Preserve the complete memory dump and analyze it with symbols matching the exact binaries. Identify the faulting instruction and trace backward to the producer of the register value. Because optimization and speculative execution are central to this architecture, source-level inspection alone may miss the path; use disassembly and register context.
Check for memory corruption, incorrect exception unwinding, hand-written assembly, compiler defects, and calls through mismatched function prototypes. An uninitialized source variable can become visible as register NaT consumption far from the original control-flow mistake.
Recovery and operational response
Restarting may clear the immediate process state but does not correct the defect. Rebuild with appropriate diagnostics, initialize all paths, and remove unsupported assembly assumptions. For production systems that still depend on Itanium software, prioritize migration because toolchain, operating-system, and hardware support are limited.
Difference from stack and buffer failures
ERROR_STACK_BUFFER_OVERRUN reports detected stack corruption and is a security-critical process failure. Error 1261 instead identifies a processor-architecture register state. Both can originate from undefined program behavior, but their crash evidence and investigation paths differ.
Example
A legacy Itanium service takes an error branch that skips assignment to a structure field later loaded into a register. Optimized code speculatively loads the value and eventually consumes its NaT state, producing 1261. Dump analysis identifies the missing initialization; retries only make the crash intermittent.
References
- Microsoft: System Error Codes (1000–1299)
- Microsoft: Analyzing a User-Mode Dump File
- Microsoft: PE Format
- Microsoft: /MACHINE target platform
Looking for a different code? Search another status or error code.