Windows 11 25H2: browser actions exit Codex after vk_swiftshader.dll Code Integrity block

[bdc8rkn66k-art]

What version of the Codex App are you using (From “About Codex” dialog)?

26.721.4979.0 (Microsoft Store, x64)

What subscription do you have?

Not provided / unknown

What platform is your computer?

Windows 11 x64, build 26200 (25H2); NVIDIA GeForce RTX 4060 Ti, driver 32.0.15.9649

What issue are you seeing?

The Codex Windows desktop app closes when a task uses the built-in browser. It reproduces in more than one chat/task, so it is not tied to one conversation.

Immediately before each closure, Windows Code Integrity logs Event ID 3033 for ChatGPT.exe:

Code Integrity determined that a process (…\ChatGPT.exe) attempted to load …\app\vk_swiftshader.dll that did not meet the Microsoft signing level requirements.

EventData: RequestedPolicy=8, ValidatedPolicy=1, Status=0xC0000428.

Windows Defender has no threat detections. The package status is OK, but after the block Microsoft Store remediation/AppX registration runs with ForceTargetApplicationShutdownOption, which forcibly closes the app. No native crash dump or WER Application Error is created because the app is being terminated by AppX registration.

This makes the desktop app unusable for browser-driven workflows.

What steps can reproduce the bug?

1. Launch Codex desktop app 26.721.4979.0 on Windows 11 25H2 (build 26200).
2. Open a new or existing Codex chat.
3. Ask the agent to perform a built-in browser action (for example, open and inspect a web page).
4. The Codex desktop window exits.
5. On restart, Microsoft Store/AppX remediation can run and repeat the forced shutdown.

Observed at least twice in separate chats after browser use.

What is the expected behavior?

Browser actions should not cause the desktop client to exit. The bundled rendering component should load successfully under Windows Code Integrity, and no Store/AppX remediation loop should be triggered.

Additional information

Troubleshooting already attempted: Windows repair install through Windows Update, Microsoft Store/AppX repair and re-registration, and clearing only browser/GPU caches. The issue persists.

Please investigate the Code Integrity rejection of the packaged vk_swiftshader.dll on Windows 11 25H2. No chat contents, account details, or local files are included in this report.

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• Codex Desktop exits when the embedded browser GPU process crashes and unsigned SwiftShader fallback is blocked #35352
• [Windows][Codex 26.715.4045.0] Page.captureScreenshot crashes GPU process after Code Integrity Event 3033 rejects bundled vk_swiftshader.dll #34133
• Codex App (Windows/Store) self-terminates ~60s after launch on older GPUs: app CIG policy blocks bundled vk_swiftshader.dll; package left "Modified/NeedsRemediation" #35132
• [Windows][26.721.4979.0] In-app Browser incident during Microsoft Store update-log lookup: startup crash loop, package remediation, and persistent deep-control timeouts #35311

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[ElierHG]

I can reproduce the same failure signature on the same Store build and OS family. My case initially looked task-specific, but the evidence shows that the affected task is simply the one that resumes the built-in Browser path.

Environment:

• Windows 11 Pro 25H2 x64, build 26200.8875
• Microsoft Store package OpenAI.Codex_26.721.4979.0_x64__2p2nqsd0c76g0
• NVIDIA RTX 3070 driver 32.0.16.1047
• Intel UHD 770 driver 32.0.101.6129
• Affected task ID: 019fa851-2db4-73e2-a713-cb385b917228

The task used Browser/node_repl to open Cloudflare’s domain-registration page. Six retries produced six Code Integrity Event 3033 records for:

ChatGPT.exe -> vk_swiftshader.dll
RequestedPolicy=8
ValidatedPolicy=1
Status=0xC0000428

At each timestamp, AppModel Runtime immediately emitted Event ID 6:

0x3CFC: Cannot create the process ... while checking the machine-level
package status ... Try reinstalling the application.

Failure-window totals:

• 6 Code Integrity 3033 events
• 30 AppModel 0x3CFC errors
• 9 AppX forced repair registrations
• 1 Store remove/reinstall
• no conventional Application Error event or crash dump

Two especially tight correlations:

06:46:15.788  Browser call opens Cloudflare registration page
06:46:20.017  Browser call records completion
06:46:20.142  Code Integrity 3033

06:53:25.534  Browser call starts
06:53:28.693  Code Integrity 3033
                (the call never records completion)

The package payload is intact. I validated ChatGPT.exe and vk_swiftshader.dll block-by-block against the signed AppxBlockMap.xml:

ChatGPT.exe:       64 blocks, 0 mismatches
vk_swiftshader.dll: 83 blocks, 0 mismatches

vk_swiftshader.dll version is 5.0.0, SHA-256:

2C8F89FA26945207260B9B019F7E1A2F4F6820741B783561F729DC13C7E82C7E

Smart App Control is off and user-mode WDAC enforcement is off. All GPUs report healthy.

The task itself remains readable: after reinstall, three backend thread/read calls completed in 11 ms, 3 ms, and 10 ms with no error. This rules out a malformed/oversized transcript. Continuing the task is what re-enters the Browser/GPU path.

After enough retries, Windows shows “This app can't open — Check the Store for more info about ChatGPT,� and the Store reinstall is required.

I have a sanitized event timeline and screenshot available. I did not attach the raw task JSONL because its Browser DOM snapshots may contain signed-in account data.

[programmerLiu0]

Additional independent reproduction

I can independently reproduce the same failure on Windows with the Microsoft Store build.

Environment

• Codex Windows package: OpenAI.Codex_26.721.4979.0_x64__2p2nqsd0c76g0
• Windows 11 x64, build 26200
• GPU:
  • NVIDIA GeForce RTX 3050 Ti Laptop GPU, driver 31.0.15.5222
  • AMD Radeon(TM) Graphics, driver 31.0.12044.3
• Distribution: Microsoft Store / MSIX

Reproduction

The failure occurred in two separate Codex conversations while Browser Use was active:

1. A Browser Use / JavaScript browser operation was running. The Codex app exited and the turn became interrupted.
2. A second conversation using Browser Use and web navigation also became interrupted after the app exited.

The failure was not tied to a particular website or project file.

Windows event evidence

At approximately 20:21:34 local time, Windows Code Integrity recorded Event ID 3033:

ChatGPT.exe attempted to load vk_swiftshader.dll
that did not meet the Microsoft signing level requirements.

At approximately 23:17:28 local time, the same Event ID 3033 occurred again for:

OpenAI.Codex_26.721.4979.0_x64__2p2nqsd0c76g0\\app\\ChatGPT.exe
OpenAI.Codex_26.721.4979.0_x64__2p2nqsd0c76g0\\app\\vk_swiftshader.dll

The event data was:

• RequestedPolicy: 8
• ValidatedPolicy: 1
• Status: 0xC0000428

No normal Application Error / WER crash entry was generated.

Startup failure and recovery

Immediately after the second Code Integrity event:

• AppModel Runtime Event ID 6 reported error 0x3CFC.
• Windows reported that the package could not create a process and recommended reinstalling the application.
• The Codex package was subsequently staged and registered again by Microsoft Store/AppX.
• Codex started successfully after the package was reinstalled.
• The current package status is Ok.

Expected behavior

A Browser Use or GPU child-process failure should be isolated and recoverable. It should not terminate the Codex desktop application or leave the MSIX package unable to launch.

Additional notes

This is an independent reproduction of the same vk_swiftshader.dll Code Integrity / Chromium GPU-process failure. The problem appears to be below the webpage and prompt layers. No session transcripts, private URLs, credentials, or workspace files are included here.

Related reports:

• [Windows app] Opening any chat triggers Code Integrity 3033 for vk_swiftshader.dll, corrupts MSIX package, and prevents relaunch (0x3CFC) #35681
• Windows desktop 26.721.4979.0 exits when in-app browser GPU process loads vk_swiftshader.dll #35635
• Codex Desktop exits when the embedded browser GPU process crashes and unsigned SwiftShader fallback is blocked #35352