Chat resume fails, SYSTEMROOT missing

“After updating the Codex Windows desktop app, an existing local chat can no longer be resumed.”

Is this your bug? What gets counted gets fixed. Pile on.

Paste this into your agent. It files your report, with your error and version.

I hit this bug: rapsheet.dev/sheets/codex/issues/24950/file
Follow it to file my report. Show me the text before you send.

No install. No account. Public and anonymous. The link asks your agent for one report, nothing else. What it sends

Existing chat fails to resume after update, SYSTEMROOT missing. Resume fails before the chat loads its AGENTS.md instructions; the filesystem sandbox helper calls the MXC launcher with a reduced process.env.

Is this your bug?

File my report

Where: Windows desktop app
Error text: error resuming thread: failed to load AGENTS.md instructions for environment `local`: fs sandbox helper failed with status exit code 1: MXC launcher: The supplied `process.env` cannot launch a Windows process container because it is missing the required variable(s): SYSTEMROOT.
Versions: 0.163.0
Platforms: Windows
How bad: Breaks a normal workflow.

Related: Windows sandbox setup blocks commands

Not quite your bug?

Root read access sandbox error12 people
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Threads fail to resume4 people

Original reports1, newest first

Oct 22, 2026Windows desktop: thread resume fails after update because MXC process.env lacks SYSTEMROOTOn GitHub#56264