Most people never delete a file larger than a few hundred megabytes, yet their Mac fills up anyway. The space rarely goes to documents. It goes to folders that apps create for themselves, grow silently, and never clean up. These are the ones we see most often in DiskDude scans.

~/Library/Caches

Every app gets its own cache folder here. Browsers store page assets, music apps store streamed tracks, and design tools store thumbnails. Individual folders are small, but together they routinely reach 10 to 20 GB.

Everything in this folder can be deleted. Apps rebuild what they need.

~/Library/Developer

If you have ever installed Xcode, this folder is probably the largest thing in your home directory.

Xcode/DerivedData holds build products for every project you have opened. It is safe to delete at any time.
CoreSimulator/Devices stores a full disk image for each iOS simulator. Old iOS versions you no longer test against can be removed from Xcode's settings.
Xcode/iOS DeviceSupport keeps symbols for every iPhone you have plugged in. Folders for iOS versions you no longer use are safe to remove.

A developer Mac with a few years of history can hold 40 to 80 GB here.

Docker Desktop

Docker stores every image, container, and volume inside a single file, usually ~/Library/Containers/com.docker.docker/Data/vms/0/data/Docker.raw. The file only grows. Pulling a few large images and forgetting them can leave 30 GB behind. Run docker system prune to reclaim it.

node_modules

A single JavaScript project can have a node_modules folder of 500 MB or more. Twenty old projects in ~/Developer add up to 10 GB of dependencies you can reinstall in minutes. DiskDude's Folders view sorts these by size so you can see which projects are worth cleaning.

~/Library/Mail and ~/Library/Messages

Mail downloads every attachment for offline access. Messages keeps every photo and video anyone has ever sent you. Both are easy to forget because the apps never show a total.

Mail has a setting to download attachments only for recent messages. Messages can be set to keep conversations for a year instead of forever.

~/Downloads

The most obvious one and still the most common. Installers, disk images, and zip files sit here long after you have used them. The Age map view highlights anything you have not opened in a year.

~/Movies and the Photos library

Screen recordings and exported video are large and easy to miss. The Photos library is a single package, so Finder shows one number for all of it. If you use iCloud Photos, turning on Optimize Mac Storage keeps full-size originals in the cloud.

Putting it together

You do not need to check these folders by hand. A full scan of a home folder takes DiskDude around ten seconds on Apple silicon. Start in the Treemap, click into the biggest block, and keep clicking until you find something you recognize. Then add it to Cleanup and review the list before removing anything.

The folders that quietly fill a Mac