[BUG] Claude Desktop 1.1.3189 severe UI lag and mouse stutter on Windows — performance regression after update

[J3-code]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Claude Desktop became severely laggy after auto-updating from 1.1.2998 to 1.1.3189 on February 16, 2026. The app had been working perfectly for weeks prior. When the Claude Desktop window is in the foreground, the mouse cursor visibly stutters, typed input lags, and the entire UI feels unresponsive. Moving the app to the background immediately relieves system responsiveness.

Root Cause Analysis

I profiled the running app and identified three contributing factors introduced or amplified by v1.1.3189:

1. Cowork VM starts on every launch (new in this version)

The update introduced a Hyper-V virtual machine that boots automatically on app start, even when the Cowork feature is not being used. The VM:

• Downloads and manages a 9.5 GB rootfs.vhdx disk image
• Runs vmcompute and vmmemCmZygote processes in the background
• Sends a keepalive ping every 2,000ms indefinitely
• Takes ~9 seconds to boot on each app launch

Prior versions logged "yukonSilver not supported, skipping" — the VM was not started. Now it starts unconditionally.

From cowork_vm_node.log:

2026-02-16 06:45:41 [info] [VM:start] Beginning startup...
2026-02-16 06:45:54 [info] [Keepalive] Starting (interval=2000ms)

2. SkillsPlugin polls every 60 seconds with React state updates

The SkillsPlugin syncs every 60 seconds, accumulating 2,177+ log entries in a single session. Each sync cycle triggers a React state update even when nothing changes (0 downloads, 0 removals every time):

2026-02-17 06:43:36 [info] [SkillsPlugin] Starting skills sync
2026-02-17 06:43:36 [info] [SkillsPlugin] Found 5 enabled skills
2026-02-17 06:43:36 [info] [SkillsPlugin] Delta: 0 to download, 0 to remove
2026-02-17 06:43:36 [info] [SkillsPlugin] Sync complete: 0 downloaded, 0 removed, 0 orphans cleaned

3. Renderer and GPU processes consume significant idle CPU

With the app window focused but idle (no streaming, no scrolling), a 5-second CPU sample showed:

Process	CPU % (of one core)	Role
Renderer (PID 3744)	13.4%	Chromium compositor
GPU process (PID 38784)	11.6%	GPU compositing
Combined	~25%	Just painting frames while idle

This is on a 3840x1600 @ 144Hz monitor with 1.5x DPI scaling. The MSIX packaging ignores all standard Electron GPU flag mechanisms (ELECTRON_EXTRA_LAUNCH_ARGS, electron-flags.conf, NVIDIA Control Panel per-app profiles), so there is no way to tune GPU compositing behavior.

Additional log signals

• React hydration error on every startup: Uncaught Error: Minified React error #418 (hydration mismatch)
• EventEmitter memory leak warning: MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added — suggests listener accumulation without cleanup
• CSP violation: Connecting to 'https://a-api.anthropic.com/v1/m' violates Content Security Policy — blocked metrics endpoint

Environment

Component	Detail
Claude Desktop	1.1.3189.0 (MSIX: Claude_1.1.3189.0_x64__pzs8sxrjxfjjc)
Electron	40.4.1
Claude Code	2.1.41
Previous working version	1.1.2998
OS	Windows 11 Pro 25H2 (Build 26200)
CPU	Intel Core i9-14900HX (24 cores / 32 threads)
RAM	64 GB
GPU	NVIDIA GeForce RTX 4070 Laptop (Driver 32.0.15.9174)
iGPU	Intel UHD Graphics (Driver 32.0.101.7079)
Monitor	Dell AW3821DW — 3840x1600 @ 144Hz, 1.5x scaling, 10-bit color
Windows Updates	KB5077181, KB5077869 (Feb 11, 2026)

Suggested Fixes

1. Don't start the Cowork VM unless the user opens a Cowork session. The VM currently boots on every launch even when unused, consuming background resources and I/O.
2. Skip SkillsPlugin sync when delta is zero. If nothing changed, don't trigger a React state update. Or increase the polling interval significantly (every 60 seconds is aggressive for a no-op check).
3. Respect ELECTRON_EXTRA_LAUNCH_ARGS and/or expose a Hardware Acceleration toggle in settings. The MSIX packaging currently ignores all standard Electron GPU flag mechanisms (see [BUG] Claude Desktop black screen with Windows HDR enabled (NVIDIA RTX 4080 + high-refresh monitor) #25801).
4. Fix the React hydration error and EventEmitter leak — these indicate the renderer is doing unnecessary work on every startup.

Related Issues

• [BUG] Claude Desktop Freeze: Cowork VM Kernel Panic Deadlocks Main Thread #26087 — Cowork VM Kernel Panic Deadlocks Main Thread (same VM, different failure mode — total freeze vs. performance degradation)
• [BUG] Claude Desktop black screen with Windows HDR enabled (NVIDIA RTX 4080 + high-refresh monitor) #25801 — Black screen with NVIDIA + high-refresh monitor (same MSIX GPU flag limitation, different symptom)
• [BUG] Claude desktop MCP "searched available tools" causes possible regression #25706 — MCP regression in 1.1.3189

What Should Happen?

Claude Desktop should run with the same performance as version 1.1.2998 and prior. The app worked flawlessly on the same hardware for weeks before this update.

Error Messages/Logs

From unknown-window.log / claude.ai-web.log:

2026-02-17 06:28:39 [error] Uncaught Error: Minified React error #418
2026-02-17 05:45:41 [warn] MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added.
2026-02-17 05:46:18 [error] Connecting to 'https://a-api.anthropic.com/v1/m' violates the following Content Security Policy directive
2026-02-17 05:46:18 [error] Error sending segment performance metrics TypeError: Failed to fetch

Process memory footprint (total ~1.3 GB across 8 Claude processes):

claude.exe (Code CLI)     — 499 MB
claude.exe (Renderer)     — 337 MB
claude.exe (Main)         — 170 MB
claude.exe (GPU)          — 151 MB
claude.exe (others x4)    — ~160 MB

Steps to Reproduce

1. Have Claude Desktop auto-update from 1.1.2998 to 1.1.3189
2. Launch Claude Desktop on a high-resolution, high-refresh-rate monitor
3. Focus the Claude Desktop window
4. Observe mouse cursor stutter and input lag while the window is focused
5. Switch focus to any other application — stutter stops immediately
6. Switch back to Claude Desktop — stutter returns

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

1.1.2998

Claude Code Version

2.1.41 — Claude Desktop 1.1.3189.0 (Electron 40.4.1)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

The update timeline from main.log:

2026-02-13 10:06  Update 1.1.2998 downloaded — last working version
2026-02-16 06:14  Update 1.1.3189 downloaded and installed — performance regression starts
2026-02-16 06:45  MSIX package installed, VM bundle downloaded (12+ GB)
2026-02-16 06:46  Cowork VM started for the first time

🤖 Generated with Claude Code

[github-actions]

Found 3 possible duplicate issues:

1. Cowork feature creates 10GB VM bundle that severely degrades performance #22543
2. [BUG] High sustained CPU usage (~100% per instance) even when idle #22275
3. [BUG] High CPU usage (5-10%) during idle and file operations on Windows #18014

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[J3-code]

Not a duplicate of any of the three listed issues.

• Cowork feature creates 10GB VM bundle that severely degrades performance #22543 is macOS-only and focuses on the VM bundle size/cleanup. This issue is Windows-specific and covers three separate problems introduced by v1.1.3189: (1) the Cowork VM starting unconditionally even when Cowork is never used, (2) SkillsPlugin polling every 60s triggering unnecessary React state updates (2,177+ entries in a single session), and (3) the MSIX packaging ignoring all Electron GPU flag mechanisms (ELECTRON_EXTRA_LAUNCH_ARGS, electron-flags.conf), causing uncontrollable renderer/GPU CPU usage on high-refresh displays. The mouse stutter symptom when the window is focused is unique to this report.
• [BUG] High sustained CPU usage (~100% per instance) even when idle #22275 is about Claude Code CLI processes consuming 100% CPU at idle — not the Desktop Electron app.
• [BUG] High CPU usage (5-10%) during idle and file operations on Windows #18014 is also about Claude Code CLI idle CPU on Windows — again, not the Desktop renderer/GPU compositor.

The root cause here is the combination of the Cowork VM overhead, SkillsPlugin polling, React hydration errors (#418), EventEmitter memory leak warnings, and the inability to pass GPU flags through the MSIX package — all introduced or amplified by the v1.1.3189 update on Windows.

🤖 Generated with Claude Code

[TheDeftones]

I have the same problem with Claude desktop. When I first started with chatty, I had the same problem there too and Claude says it might be because they both use Electron apps? Although it acknolwedged that the issue with Claude is more recent. Still, it's super annoying.

[yarodevuci]

same here...

[felldo]

I have the same issue with a tripple monitor setup. My main monitor, an LG ultrawide WQHD monitor and on each side a 16:9 LG WQHD. It only starts to visible lag the mouse when using it on the ultrawide monitor

[Gene86-beep]

I'm experiencing a related issue on the latest version of Claude Desktop for Windows that I wanted to add here since it aligns with the Hyper-V VM auto-start problem described in this thread.

Symptoms:

• Mouse clicks stop registering after using the PC for a period of time
• Phantom mouse clicks occur when I'm not touching the mouse at all
• The issue persists across multiple different mice, ruling out hardware
• Problem occurs even when Cowork is not actively being used

What I've tried (did NOT fix the issue):

• Updated Windows
• Updated GPU drivers
• Restarted PC multiple times
• Uninstalled and reinstalled Claude Desktop (latest version)

What DID fix the issue:

• Ending the Hyper-V vmcompute task in Task Manager temporarily resolved it
• Running bcdedit /set hypervisorlaunchtype off and restarting fully resolved the phantom click and input issues
• Note: after uninstalling Claude Desktop, the Hyper-V services (vmcompute and others) were still running and the mouse problems persisted until I disabled the hypervisor via bcdedit

The problem returned immediately after reinstalling Claude Desktop, confirming the Hyper-V VM that Cowork spins up is the root cause. The VM still appears to start unconditionally on app launch regardless of whether Cowork is being used.

This is a significant usability issue — it effectively makes the PC unusable for normal work while Claude Desktop is installed. I'd love to keep using Cowork but can't until the VM is prevented from auto-starting when Cowork isn't active.

System: Windows 11, latest Claude Desktop version downloaded from claude.com/download (March 2026)

[cambriel-cpu]

I'm having this issue too, and seemed to make progress by creating a batch file that runs Claude with a --disable-gpu flag to disable hardware acceleration. Claude itself suggested the fix, which seems to work. However, it's an obvious workaround. The right fix is probably to offer a disable hardware acceleration toggle in settings.

[sandros94]

It has something to do with gpu hardware acceleration, or more simply frame scheduling.

One of my monitors is a normal gsync compatible panel, which suffer badly for <70hz displaying, and it seems that now claude desktop has dynamic frame generation based no UI or system updates. This causes electrop to constantly go from 0fps rendering upto the current monitor max one, causing a spike in desyncronization between cpu and gpu busy state and the other forced to a wait state

EDIT:

also, for those interested in disabling gpu acceleration you can simply click the burger menu top left -> help -> troubleshooting -> Disable Hardware Acceleration

Still remember when this was a vscode issue a few years ago...

[sanblu]

I have the same issue on two separate computers. It's extremely annoying, mouse stutters and the dark background slightly flickers. I'm surprised this hasn't been fixed for more than half a month as it's a serious issue. (Not sure if that matters, but my setup is similar to what others described: Windows, ultrawide screens, RTX 3080/RTX 4080.)

EDIT: The workaround as suggested by sandros94 helped. When disabling hardware acceleration the issue disappears.

[wywywywy]

It's definitely VRR (e.g. G-Sync) related as @sandros94 mentioned. Turning off G-Sync fixes it.

You can use the Nvidia Control Panel or the Nvidia Profile Inspector to set Claude to use fixed refresh rate, but every time you switch between apps the monitor has the re-adjust so it's not a good solution.

ChatGPT Desktop, and many Electron apps, also suffer from this.

But it's definitely fixable, because some Electron apps like VS Code / Slack / Discord / Notion / etc don't suffer from this nowadays.