How to Fix Stage Manager Minimized Windows Lost in macOS Sequoia 15.x
Symptom: After using Stage Manager on macOS Sequoia for a long period, minimizing a window causes it to disappear from both the side strip and the Dock, even though the app is still shown as "running."
Start with Fix 1: Kill the WindowManager Process. If the issue persists after that, try Fix 2: Toggle "Recent Apps" in Strip. Full Terminal commands and step-by-step instructions are in each section below.
Why this happens
This is a layering bug in Sequoia's WindowManager. The window gets assigned to a "null" Space or becomes hidden behind the active desktop background layer when the Stage Manager "Strip" fails to update its icon cache.
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: Kill the WindowManager Process
- Open Terminal.
- Run the following command:
killall WindowManager
- Your screen will flicker briefly as the UI process restarts. Your windows should reappear in the Stage Manager strip.
Fix 2: Toggle "Recent Apps" in Strip
- Go to System Settings > Desktop & Dock.
- Under Stage Manager, click Customize....
- Toggle Recent apps off and then back on to force the UI to re-index the open window handles.
Recommended Tool: CleanMyMac
UI glitches like disappearing windows are often a symptom of low "Window Server" memory. Use CleanMyMac to optimize RAM and clear system junk, ensuring the WindowManager has enough overhead to manage app stacks.