What does Windows error code 813 (ERROR_CPU_SET_INVALID) mean?

ERROR_CPU_SET_INVALID

The specified CPU Set IDs are invalid.

ERROR_CPU_SET_INVALID is Win32 error 813 (0x32D) and belongs to CPU Set selection.

Where the result appears

• SetProcessDefaultCpuSets or SetThreadSelectedCpuSets.
• A scheduler policy restored after topology changed.
• Software using CPU Set IDs obtained on another machine or boot.
• A process mixing CPU Sets with processor-group assumptions.

Likely causes

• one or more supplied CPU Set IDs are absent from the current topology.
• the selected logical processor became unavailable or parked by policy.
• IDs were truncated, confused with processor numbers, or reused after restart.
• the request contains a combination not valid for the target process or thread.

What to verify

Verify whether one or more supplied CPU Set IDs are absent from the current topology. Check complete list returned by GetSystemCpuSetInformation together with requested IDs, allocation tags, processor groups, and efficiency classes.

Handling, retry, and recovery

Enumerate CPU Sets again and rebuild the selection from current IDs. Never treat a CPU Set ID as a durable logical-processor number or reuse a cached list after topology changes.

Difference from nearby codes

The code identifies invalid CPU Set identifiers, not ordinary affinity-mask exhaustion or a performance complaint.

Practical example

A service stores CPU Set IDs in configuration and reuses them after a VM changes vCPU topology.

References

• Microsoft: System Error Codes (500–999) — reference for error 813.
• Microsoft: CPU Sets — reference for error 813.
• Microsoft: GetSystemCpuSetInformation — reference for error 813.