Split writable root sandbox failure

“On native Windows 11, Codex CLI exec_command fails before launching even a read-only pwd command.”

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/9810/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

Growing. 1 report in the last 7 days and none the week before.

Windows unelevated sandbox rejects split writable roots, blocking commands. Commands fail before the process starts, even a read-only one, and the session refuses to run unsandboxed; enabling Full access did not clear it.

Is this your bug?

File my report

Where: Windows sandbox
Error text: windows unelevated restricted-token sandbox cannot enforce split writable root sets directly; refusing to run unsandboxed
Versions: 0.162.0 to 26.1002.52244
Platforms: Windows
How bad: Stops work: a core feature can't be used. Some reports say it blocks them completely.

Part of: Windows sandbox setup blocks commands18 bugs

Sandbox setup refresh fails308 people
Sandbox fails at deny-read ACLs10 people
Setup refresh error blocks commands23 people
Sandbox setup lock failure12 people
Sandbox fails on WSL UNC paths4 people
Windows sandbox setup fails validating long cua_node runtime paths11 people
Windows setup stops without UAC3 people
Sandbox ACL update failure2 people
Sandbox ACL refresh fails2 people
Managed networking sandbox error2 people

Show all 17Show only the largest 10

Sandbox refresh fails on old runtime2 people
Sandbox fails on Google Drive2 people
Sandbox provisioning failed2 people
Windows sandbox provisioning fails3 people
Windows sandbox setup access denied2 people
Root read access sandbox error12 people
Shell and Node tools fail with MXC 0x80070020 on Windows2 people

Not quite your bug?

Existing files denied write access2 people

Original reports3, newest first

Nov 3, 2026Windows CLI 0.166.0: exec_command blocked by policy in read-only and split writable-root failure in workspace-writeOn GitHub#59314
Oct 14, 2026Windows scheduled heartbeat omits cwd write permission and fails before command startup with split writable root setsOn GitHub#53863
Oct 8, 2026Windows delegated task cannot start PowerShell: unelevated sandbox rejects split writable rootsOn GitHub#52252