Codex App 26.429.61741 causes persistent high CPU usage in renderer and severe UI lag on macOS

[xulzee]

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

Affected version: 26.429.61741 Last known good version: 26.422.21637

What subscription do you have?

ChatGPT Pro

What platform is your computer?

Darwin 25.1.0 arm64 arm

What issue are you seeing?

After updating the Codex desktop app to version 26.429.61741, the app becomes noticeably sluggish even in a fresh conversation and an empty workspace. Basic UI interactions such as selecting text, clicking around, and switching focus have visible delays.

The main symptom is sustained high CPU usage from the Electron renderer process:

• Codex Helper (Renderer) stays around 100%-170% CPU
• Codex Helper GPU process also shows elevated CPU usage
• This happens with only one Codex conversation open
• Restarting Codex does not resolve the issue
• The current workspace is empty, so this does not appear to be caused by project size or file indexing

I tried the following troubleshooting steps:

• Restarted Codex completely
• Opened a fresh conversation
• Used an empty workspace
• Switched back to Local instead of a remote SSH target
• Disabled/uninstalled Browser Use
• Resolved an unrelated high-CPU BackgroundShortcutRunner process on macOS

None of those fixed the issue on 26.429.61741.

Downgrading the Codex app to 26.422.21637 immediately resolved the problem on the same machine and workspace. CPU usage returned to normal and the UI became responsive again.

Some relevant observations from the logs while running 26.429.61741:

• Repeated remote connection selection/reconciliation for a discovered SSH host
• Repeated Browser Use native pipe/sidebar initialization
• Repeated errors syncing the workspace_dependencies experimental feature:

unsupported feature enablement `workspace_dependencies`: currently supported features are apps, memories, plugins, remote_control, tool_search, tool_suggest, tool_call_mcp_elicitationI also captured a macOS sample of the high-CPU renderer process. The hot path appears to be on the Electron/V8 main thread, consistent with a frontend renderer loop or repeated UI state reconciliation.

Expected behavior:

The Codex desktop app should remain responsive and the renderer process should not sustain ~100%+ CPU while idle or during basic UI interactions.

Actual behavior:

On 26.429.61741, the renderer process continuously consumes high CPU and the UI becomes sluggish. Downgrading to 26.422.21637 fixes the issue.

What steps can reproduce the bug?

I do not have a code snippet because this appears to be a desktop app/UI performance regression rather than a project-specific issue.

Steps to reproduce:

1. Install or update the Codex desktop app to version 26.429.61741.
2. Launch Codex on macOS.
3. Open a fresh conversation in an empty local workspace.
4. Do not run any tools or commands.
5. Try basic UI interactions such as selecting text, clicking in the conversation, switching focus, or opening a new conversation.
6. Open Activity Monitor and check the Codex processes.

Observed result:

• Codex Helper (Renderer) continuously uses around 100%-170% CPU.
• The Codex UI becomes noticeably sluggish.
• Basic interactions such as text selection and clicking have visible latency.
• Restarting the app does not resolve the issue.

Troubleshooting already attempted:

• Restarted Codex completely.
• Opened a new conversation.
• Used an empty workspace.
• Switched back to Local instead of a discovered remote SSH target.
• Disabled/uninstalled Browser Use.
• Resolved an unrelated high-CPU macOS BackgroundShortcutRunner process.
• Verified that the issue still occurred after those steps on 26.429.61741.

Control test:

• Downgrading the Codex desktop app to 26.422.21637 immediately resolves the issue on the same machine and workspace.
• With 26.422.21637, the UI is responsive and Codex Helper (Renderer) no longer stays at ~100%+ CPU.

What is the expected behavior?

The Codex desktop app should remain responsive in a fresh conversation and empty local workspace.

Basic UI interactions such as selecting text, clicking, switching focus, and opening a conversation should be smooth. The Codex Helper (Renderer) process should not continuously consume around 100%-170% CPU while the app is idle or during simple UI interactions.

Downgrading to 26.422.21637 restores this expected behavior, so I would expect 26.429.61741 to behave similarly.

Additional information

No response

[github-actions]

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

• Codex Desktop renderer spins at high CPU while codex MCP servers are idle #20435
• CPU usage problem #19942
• Excessive CPU Usage #19665
• Mac App stuck on splash logo: renderer pushes unsupported workspace_dependencies feature in tight retry loop, init never completes #19682
• Codex Desktop sluggish after today's update to 26.429.20946 #20547

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