When you browse through files in the macOS Finder, you will notice that image files (JPEGs, PNGs) and documents (PDFs, text files) do not use generic icons. Instead, macOS automatically generates a tiny, low-resolution preview of the actual image or the first page of the document and uses that as the file’s icon.
While this is great for quickly finding a specific photograph in a folder of hundreds of images, it is a massive performance bottleneck on older Macs. If you open a folder containing 5,000 raw photos, the Finder will aggressively try to generate 5,000 unique thumbnails in the background, maxing out your CPU, slowing down your computer, and draining your battery.
You can force macOS to use fast, generic icons for all files by disabling the automatic icon preview feature.
How to Disable Icon Previews in Finder
You can turn off icon generation via the Finder’s View Options.
- Open a Finder window on your Mac.
- Navigate to the folder where you want to disable the previews (or just stay in your Home directory to apply it globally).
- In the top menu bar, click on View.
- Select Show View Options (or press
Cmd + J). - A floating settings window will appear. Look near the bottom of this window.
- Uncheck the box labeled Show icon preview.
- (Crucial Step) If you want this change to apply to every single folder on your entire hard drive, click the Use as Defaults button at the very bottom of the window.
- Close the View Options window.
Instantly, all of your files will revert to generic system icons (a blue JPEG icon, a white PDF icon). The Finder will run significantly faster because it no longer has to render thousands of images every time you open a directory.