apply_patch "Update"/"Delete" always fails on Windows Desktop: fs sandbox helper stack overflow (0xC0000005 in essctl.dll); "Add" works

apply_patch "Update"/"Delete" always fails on Windows Desktop: fs sandbox helper stack overflow (0xC0000005 in essctl.dll); "Add" works

Describe the bug

On Codex Desktop for Windows (version 26.803.10989.0), apply_patch operations that modify or delete an existing file fail deterministically before applying anything. The tool reports that the filesystem sandbox helper crashed with a stack overflow:

apply_patch verification failed: Failed to read <file>: fs sandbox helper failed with status exit code: 0xc0000005: thread '<unknown>' (PID) has overflowed its stack

Creating a new file with apply_patch works fine.

To Reproduce

1. In a Codex Desktop session on Windows, use apply_patch to create a small text file (e.g. work/foo.txt with two short lines). This succeeds.
2. Use apply_patch to change one line of that file. This fails with the message above.
3. Use apply_patch to delete that file. This fails with the same message.
4. Create another new file with apply_patch. This succeeds again.

The failure is independent of file size or content (reproduced with a two-line ASCII file). It is not caused by long lines, Unicode, or patch syntax.

Expected behavior

Update and Delete should apply like Add does.

Environment

• Codex Desktop version: 26.803.10989.0 (Windows, ChatGPT sign-in)
• OS: Windows 10 Pro 22H2 (10.0.19045), 64-bit
• Session type: projectless chat under the user Documents\Codex folder

Additional context

• Windows Application Event Log shows repeated codex.exe crashes with exception code 0xC0000005 in essctl.dll (offsets 0x102ab / 0x22db6), timestamped exactly when apply_patch fails.
• The same helper crash occurs for Update and Delete on any existing file; Add does not trigger it, which suggests the crash happens when the helper reads an existing file during verification.
• Local Codex log (target codex_core::tools::router) records: apply_patch verification failed: Failed to read ...: fs sandbox helper failed with status exit code: ... has overflowed its stack.
• Workaround used: delete the file with a shell command, then re-create it with apply_patch (the Add path still works). This only works for scratch files; normal in-repo edits are blocked.

Related issues

• #29178 (fs-helper fails when global proxy env is set) - different failure mode
• #29072 (codex-windows-sandbox-setup.exe cannot launch from package path) - different failure mode
• #14211 / #13965 (Windows sandbox child-process launch path) - possibly related underlying sandbox path