How do I fix Stage Manager High CPU Usage in macOS Sequoia 15.x?

Three approaches in order of safety: (1) Clear WindowManager Cache; (2) Disable Recent Apps Previews. Full Terminal commands and System Settings paths are inside each section.

Is this fix confirmed for macOS Sequoia 15.x?

Yes — verified on macOS Sequoia 15.x. Article is updated when Apple ships a point release that changes the symptom or fix.

How to Fix Stage Manager High CPU Usage in macOS Sequoia 15.x

Symptom: Your Mac's fans spin up or performance drops when Stage Manager is active in macOS Sequoia. Activity Monitor shows WindowManager using >100% CPU.

TL;DR fix

Start with Fix 1: Clear WindowManager Cache. If the issue persists after that, try Fix 2: Disable Recent Apps Previews. Full Terminal commands and step-by-step instructions are in each section below.

Why this happens

Sequoia's Stage Manager uses a new "live preview" engine that can loop if certain Electron-based apps (like Discord or Slack) are in the sidebar.

Recommended Troubleshooting Tool

Before proceeding with manual fixes, we recommend using CleanMyMac X. Quickly identify high CPU apps and optimize system memory with one click.

Fix 1: Clear WindowManager Cache

Open Terminal.
Run:

rm -rf ~/Library/Caches/com.apple.WindowManager

Kill the process:

killall WindowManager

Fix 2: Disable Recent Apps Previews

Go to System Settings > Desktop & Dock.
Click Stage Manager Details.
Toggle OFF "Show Recent Apps".

Recommended Tool: iStat Menus

To monitor CPU spikes in real-time:

- Get iStat Menus to see exactly which app is triggering Stage Manager lag and monitor your system's health from the menu bar.

Tested and documented by the MacDebug team — about MacDebug. See also Stage Manager Flicker on macOS Sequoia, Sequoia Stage Manager Window Flickering, or browse all guides on macdebug.