How do I fix Finder QuickLook Memory Leaks in macOS Tahoe 26.2?

Three approaches in order of safety: (1) Force Restart QuickLook Services; (2) Clear the QuickLook Cache. Full Terminal commands and System Settings paths are inside each section.

Is this fix confirmed for macOS Tahoe 26.2?

Yes — verified on macOS Tahoe 26.2. Article is updated when Apple ships a point release that changes the symptom or fix.

How to Fix Finder QuickLook Memory Leaks in macOS Tahoe 26.2

Symptom: Selecting files in Finder causes QuickLookUIService memory usage to climb indefinitely, eventually triggering "Your system has run out of application memory."

TL;DR fix

Start with Fix 1: Force Restart QuickLook Services. If the issue persists after that, try Fix 2: Clear the QuickLook Cache. Full Terminal commands and step-by-step instructions are in each section below.

Why this happens

The Tahoe beta build of QuickLook has a regression where file previews (especially PDFs and HEIC images) are not purged from the RAM buffer after the preview window is closed.

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: Force Restart QuickLook Services

Open Terminal.
Run the following command to kill the leaking processes:

killall QuickLookUIService && killall qlmanage

Finder will automatically restart these services as needed.

Fix 2: Clear the QuickLook Cache

In Terminal, run:

qlmanage -r cache

Then reset the daemon:

qlmanage -r

Tested and documented by the MacDebug team — about MacDebug. See also Fix macOS "Finder" High CPU Usage, Finder Slow or Lagging on macOS Tahoe 26.2, or browse all guides on macdebug.