Sandbox fails on WSL UNC paths

“When resuming or starting a task, the Windows sandbox attempts to apply Windows ACLs to the WSL UNC workspace and fails before the task starts.”

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/13776/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

Quiet. No reports and thumbs-up in the last two weeks, down from 1 a week at the mid-September peak.

Windows sandbox setup fails on WSL UNC workspace paths. With Agent Environment set to Native Windows, ACL writes on \\wsl.localhost or \\wsl$ workspaces fail with GetSecurityInfo error before tasks start.

Is this your bug?

File my report

Where: Windows sandbox
Error text: helper_unknown_error: setup refresh had errors
Versions: 26.915.31945 to 26.930.41038
Platforms: Windows
How bad: Some reports say it used to work. 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
Split writable root sandbox failure3 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?

WSL agent commands fail to spawn70 people

Original reports3, newest first

Oct 5, 2026Windows sandbox setup refresh fails on WSL UNC workspace (GetSecurityInfo error 1)On GitHub#51170
Sep 21, 2026[Windows][WSL] Mixed Windows/WSL projects unusable: Windows agent fails on WSL UNC workspace, WSL agent hangs app startup, Agent Environment is globalOn GitHub#47115
Sep 19, 2026Windows-native agent sandbox fails when workspace is on a WSL UNC path: setup refresh had errorsOn GitHub#46640