ChatGPT Desktop for Windows crashes during startup due to Chromium GPU/sandbox failure; workaround is --disable-gpu --disable-gpu-sandbox

Preface: ChatGpt figured all this out with me. and compiled all this info for this report. Requested i also include this session ID: no-active-thread-01a0abe7-7eed-71c1-bbfa-314f9fc9bb9a

Environment

• Windows 11 Pro 25H2
• OS build: 26200.9457
• ChatGPT Desktop / OpenAI.Codex package: 26.908.9136.0
• Codex CLI: 0.154.0-alpha.6.2
• GPU: NVIDIA GeForce RTX 4090
• NVIDIA driver was updated during troubleshooting; issue persisted
• Revit 2027 was also in use while testing an external MCP connector
  Summary
  ChatGPT Desktop intermittently crashes immediately during startup on Windows. The issue first became apparent while testing third-party MCP servers for Revit, but troubleshooting indicates that the MCP servers themselves are not the root cause.
  The desktop logs show Chromium child processes failing to launch, including the GPU process, Storage Service, and Data Decoder Service, all with exit code 21. I also have repeated Codex Windows sandbox setup failures with:
  helper_sandbox_lock_failed: lock sandbox bin dir ... failed: SetNamedSecurityInfoW sandbox dir failed: 5
  Windows error 5 is Access Denied.
  The reliable workaround is launching ChatGPT Desktop with:
  --disable-gpu --disable-gpu-sandbox
  With those two flags, ChatGPT Desktop launches and works correctly, including ChatGPT Work communicating successfully with a Revit MCP connector.
  Important MCP testing
  I tested two unrelated Revit MCP implementations:

1. BIMwright RvtMcp
2. AUTOM8LABS MCP Connector for Revit
   Both appeared to coincide with ChatGPT Desktop startup failures initially.
   However, I later isolated AUTOM8LABS and verified that it works correctly outside the desktop app:
   Codex CLI -> AUTOM8LABS MCP -> Revit 2027
   successfully connected and returned:

• Revit: Autodesk Revit 2027, build 27.2.0.39
• Document: Project1 during the initial test
• Active view: Project View
  I later successfully used the same connector through ChatGPT Work when ChatGPT Desktop was launched with:
  --disable-gpu --disable-gpu-sandbox
  ChatGPT Work successfully connected to my actual Revit model and reported:
• Revit 2027
• Model: 26-1500 (PD-ApexNC)_Arch_R27
• Active view: Partial Section - Stair East
  This suggests that the MCP server and Revit connection are working and that the failure is occurring in the ChatGPT Desktop / Chromium / Windows sandbox startup path.
  Reproduction / troubleshooting performed
• Freshly reinstalled ChatGPT Desktop
• Reset ChatGPT Desktop through Windows Settings
• Removed all third-party MCP entries from .codex\config.toml
• Confirmed ChatGPT config contained no AUTOM8LABS entry
• Removed BIMwright RvtMcp completely
• Updated NVIDIA RTX 4090 driver
• Verified the AUTOM8LABS bridge executable launches normally as the current user
• Verified Codex CLI config parses successfully
• codex doctor reports the environment as healthy aside from Defender/search warnings
• Verified Codex CLI can initialize and call the AUTOM8LABS MCP
• Verified the AUTOM8LABS MCP can successfully ping Revit
  Observed desktop log errors
  The ChatGPT Desktop log includes:
  Recoverable Chromium child process gone exitCode=21 ... processType=GPU reason=launch-failed
  Recoverable Chromium child process gone exitCode=21 name="Storage Service" processType=Utility reason=launch-failed
  Recoverable Chromium child process gone exitCode=21 name="Data Decoder Service" processType=Utility reason=launch-failed
  followed by:
  Failed to load bundle ... ERR_FAILED (-2) loading 'app://-/index.html'
  Another crash produced a Crashpad dump identifying the crashing process as the browser process.
  The Codex sandbox log repeatedly reports:
  helper_sandbox_lock_failed: lock sandbox bin dir C:\Users<user>.codex.sandbox-bin failed: SetNamedSecurityInfoW sandbox dir failed: 5
  Working workaround
  ChatGPT Desktop launches reliably when the packaged application is started with:
  --disable-gpu --disable-gpu-sandbox
  Using --disable-gpu alone was not consistently sufficient when Revit was running.
  I previously tested --disable-software-rasterizer as well, but that was not a valid workaround because it removed Chromium's software rendering fallback and produced a fatal GPU process isn't usable. Goodbye. condition.
  Expected behavior
  ChatGPT Desktop should launch normally without requiring Chromium GPU/sandbox flags, and loading an external stdio MCP server should not cause or expose a desktop startup failure.
  Actual behavior
  ChatGPT Desktop can terminate during startup before a usable window appears. Logs indicate Chromium GPU/utility child-process launch failures and a separate Codex Windows sandbox ACL failure.
  Attachments
  I can provide:
• codex-desktop-1e4cfafe-8d04-46b3-83a8-f00a611ce404-25708-t0-i1-172758-0.log
• sandbox.2026-09-15(1).log
• Crashpad .dmp files and matching _sidecar.json
• Additional startup logs from successful and failed launches
  Please let me know if you would like the Crashpad dump, full Codex configuration with sensitive information removed, or any additional diagnostics.

4201e91d-193f-4b1b-bb58-7e88d54be179_sidecar.json
codex-desktop-1e4cfafe-8d04-46b3-83a8-f00a611ce404-25708-t0-i1-172758-0.log
sandbox.2026-09-15(1).log

Start with the attached desktop, sandbox, and Crashpad logs, focusing on the Chromium child-process exit code 21 and the SetNamedSecurityInfoW access-denied failure. Reproduce startup with and without --disable-gpu --disable-gpu-sandbox, then determine whether the desktop startup path or Windows sandbox setup is responsible; done means normal startup without those flags.