[Windows 10] Unified ChatGPT app causes persistent Microsoft Defender CPU usage and system-wide mouse stuttering

[hurlyliu-del]

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

26.707.91948

What subscription do you have?

Plus

What platform is your computer?

Microsoft Windows NT 10.0.19045.0 x64 — Windows 10 22H2, OS Build 19045.6466

What issue are you seeing?

After the standalone Codex app was upgraded to the new unified ChatGPT desktop app, launching the app began causing severe system-wide mouse stuttering for approximately 10–15 seconds.

After the initial stuttering stops, Microsoft Defender's Antimalware Service Executable (MsMpEng.exe) continuously consumes approximately 5%–17% CPU, even when the ChatGPT app has been completely idle for several minutes.

Closing the unified ChatGPT desktop app causes Defender CPU usage to immediately return to approximately 0%.

This issue also occurs when I use only Chat and never enter or use Codex.

What steps can reproduce the bug?

1. Enable Microsoft Defender real-time protection.
2. Launch the unified ChatGPT desktop app installed from Microsoft Store.
3. Observe severe system-wide mouse and UI stuttering for approximately 10–15 seconds during startup.
4. Leave the app completely idle for at least five minutes.
5. Observe Antimalware Service Executable continuously consuming CPU.
6. Fully close the ChatGPT desktop app.
7. Observe Defender CPU usage immediately return to approximately 0%.

What is the expected behavior?

The ChatGPT desktop app should start without causing system-wide stuttering, and Microsoft Defender should return to idle after completing any initial application scan.

Actual behavior

• The entire system stutters for approximately 10–15 seconds when the app starts.
• Mouse movement becomes visibly intermittent.
• Defender continues using approximately 5%–17% CPU indefinitely while the app remains open.
• Closing the app immediately stops the Defender CPU usage.
• Temporarily disabling Defender real-time protection also immediately stops the CPU usage.

Additional information

A fresh Microsoft Defender performance recording, captured after uninstalling Microsoft PC Manager and reinstalling ChatGPT from Microsoft Store, reported:

• ChatGPT.exe: 1,647 real-time scans, approximately 1,295.58 ms total duration
• Bundled app\resources\codex.exe: 474 scans, approximately 348.08 ms total duration
• .codex\config.toml: 8 scans, approximately 103.24 ms total duration
• Additional scans of temporary CRX_INSTALL JavaScript files, the desktop app's Chromium cache, extension state, service worker data, and AMSI memory content

Although the ordinary file-scan duration is not sufficient by itself to explain all of the sustained CPU usage, the problem consistently stops when the ChatGPT app closes or Defender real-time protection is disabled.

Defender also repeatedly requested permission to submit .codex\config.toml as a sample for cloud analysis. Disabling automatic sample submission did not resolve the CPU issue.

Defender protection history contains no malware detection or quarantine event for ChatGPT or Codex.

Troubleshooting already completed

The following did not resolve the issue:

• Restarting Windows
• Leaving the app completely idle
• Using only Chat without entering Codex
• Updating the ChatGPT desktop app
• Repairing the application
• Completely uninstalling and reinstalling it from Microsoft Store
• Uninstalling Microsoft PC Manager
• Temporarily disabling automatic sample submission
• Adding and subsequently removing folder exclusions
• Adding and subsequently removing process exclusions for ChatGPT.exe and Codex.exe
• Changing [windows] sandbox from "elevated" to "unelevated"
• Setting sandbox_private_desktop = false
• Disabling or changing the Windows sandbox configuration

All Defender exclusions and diagnostic sandbox changes have now been removed or restored to their defaults.

Environment

• App: New unified ChatGPT desktop app with Codex
• Installation source: Microsoft Store
• Current app version: 26.707.91948
• Previous affected versions observed: 26.707.6957.0, 26.707.9981.0, and 26.707.12708.0
• OS: Microsoft Windows NT 10.0.19045.0 x64
• Windows edition: Windows 10 22H2
• OS build: 19045.6466
• Microsoft Defender platform observed during testing: 4.18.26060.3008
• Microsoft Defender engine: 1.1.26060.3008
• Advanced Account Security: Not enabled
• OpenAI Support case: 11394524

Additional notes

The issue began immediately after the former standalone Codex application was upgraded into the unified ChatGPT desktop application. The previous standalone ChatGPT and Codex applications did not cause this behavior on the same computer.

I can provide the original Defender .etl performance recordings privately if an OpenAI maintainer needs them. I have not attached the raw ETL publicly because it may contain local file paths and other machine-specific information.

[github-actions]

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

• Windows Codex app causes mouse stutter during startup and task switching without CPU/Disk saturation #33074

Powered by Codex Action

[Mahkhmood9]

What kind of system you got? you;d be surprise how much consuming it is?

8gb , cpu on a laptop from 5 years ago , isnt enough

you cant have a i5-10211U Cpu @ 1.60ghz
without having a VERY bad day!

but the cli version is actually lightweight----
I give it credit , it doesnt consume 2gb of ram like the other coding apps --- so its the correct apporch ---

regarding the windows app... Well , I am not a fun of the whole thing being 1.8gb on the system lol!
its totally fine if binaries need to be packed , but seriosly....

same with Cursor shipping huge binaries like this ---- for now its okay I give it a pass, because the Vscode-ide , is "only" 300mb whic is fine with me , considering it doesnt mock 3gb of ram usage...
I only get 300mb of ram usage which is very fair

For example Minecraft only needs 2gb of ram , to be able to run smoothly on a laptop (considering you lower the res to 1024x768), considering you use the latest versions of java - which are efficent

[Mahkhmood9]

as per models ...

concepts, and templates are the same thigns for the models in how they should think and do think now

[hurlyliu-del]

My laptop specifications
处理器 AMD Ryzen 9 5900HX with Radeon Graphics 3.30 GHz
机带 RAM 32.0 GB (31.4 GB 可用)
存储 3.73 TB SSD Predator SSD GM7 M.2 4TB, 954 GB SSD PM81024GPMCB27BTF-E13T4M
显卡 NVIDIA GeForce RTX 3080 Laptop GPU (16 GB), AMD Radeon(TM) Graphics (496 MB)
系统类型 64 位操作系统, 基于 x64 的处理器

[Mahkhmood9]

My laptop specifications 处理器 AMD Ryzen 9 5900HX with Radeon Graphics 3.30 GHz 机带 RAM 32.0 GB (31.4 GB 可用) 存储 3.73 TB SSD Predator SSD GM7 M.2 4TB, 954 GB SSD PM81024GPMCB27BTF-E13T4M 显卡 NVIDIA GeForce RTX 3080 Laptop GPU (16 GB), AMD Radeon(TM) Graphics (496 MB) 系统类型 64 位操作系统, 基于 x64 的处理器

as per , system-wide mouse shuttering --- I personall have no idea how to start debugging it

[equilento]

Having the same issue.
AMD ryzen 7950x3D, 96gb 6600MT/s RAM, rtx 4090.

It is not the pc.

[youbi449]

same issue ryzen 7800X3D mouse stuttering 24gb ram

[hurlyliu-del]

Update — issue no longer reproducible as of July 20, 2026

Today, the problem unexpectedly disappeared without any additional troubleshooting on my side.

Current behavior:

• ChatGPT launches normally with no system-wide mouse stuttering or temporary system freeze.
• Antimalware Service Executable (MsMpEng.exe) remains at approximately 0–0.1% CPU while ChatGPT is open and idle.
• ChatGPT and Codex can now be used normally without persistent Defender CPU usage.
• Microsoft Defender real-time protection remains enabled.
• All temporary Defender exclusions previously used for testing have been removed.

Windows deployment logs show that the Microsoft Store package was updated from 26.707.12708.0 to 26.715.4045.0 on July 19. The current internal app component version reports 26.715.31925.

Microsoft Defender security intelligence was also updated on July 20, so I cannot determine with certainty whether the issue was resolved by the ChatGPT application update, the Defender definition update, or an interaction between the two.

However, the timing strongly suggests that a recent update resolved the compatibility problem. I will continue monitoring and report back if the issue returns.