How to show the Library folder on Mac, and what is inside

1. Open it from the Go menu

Apple’s Finder guide gives the two quickest routes. In Finder, press and hold the Option key, open the Go menu, and Library appears between Home and Computer; choose it. Or choose Go → Go to Folder and type ~/Library, where the tilde stands for your home folder. Press Return and the folder opens.

There are three Library folders and only one is yours. ~/Library belongs to your user account and holds app data. /Library, at the top of the disk, holds items shared by every user. /System/Library belongs to macOS and is protected; nothing in this guide applies to it.

2. Keep it visible if you visit often

Open your home folder in Finder, choose View → Show View Options, and select Show Library Folder. The folder then appears alongside Documents and Downloads until you clear the checkbox. It is a convenience, not a change to what the folder contains.

Add it to the Finder sidebar by dragging it there if you prefer. Either way, keep the habit of measuring before deleting; visibility is what makes accidental deletion possible.

3. What the big folders hold

Sizes vary by what you use, but the same folders dominate most Macs. Apple’s Storage settings count most of this as System Data, which is why the category grows without any file you remember saving.

• Caches: rebuildable working files per app. Safe to review once the app is closed; expect the app to recreate what it needs.
• Application Support: settings, databases and licenses for apps. Review only; deleting a folder resets or breaks its app.
• Containers and Group Containers: data for sandboxed apps, including Mail and Messages. Leave them and use the app’s own controls.
• Developer: Xcode’s Derived Data, archives and simulators. Covered by the Xcode and simulator guides.
• Mail and Messages: message stores and attachments. Covered by their own guides; never trim them in Finder.
• Mobile Documents and CloudStorage: local copies of iCloud Drive and other cloud drives. Change sync settings, not files.
• Logs and Saved Application State: usually small; rarely worth attention.

4. Measure before you touch anything

Select a folder and choose File → Get Info to see its size, or run du -sh ~/Library/Caches in Terminal for a quick read-only figure. Both take time on a large folder. A disk scanner with Full Disk Access lists every Library folder at once with allocated sizes and a label, so you can compare Caches against Containers before opening either.

Write down the two or three largest folders and the app each belongs to. That list, not the Library as a whole, is what you act on.

du -sh ~/Library/Caches

5. What not to delete

Never touch /System/Library, and do not delete Application Support, Containers or Preferences wholesale. Remove cache folders only for apps you have quit, move them to the Trash rather than deleting immediately, and empty the Trash after the app has run once and behaved. If a folder returns to the same size within days, the app is producing it deliberately; the recurring-growth guide covers how to trace that.

ClearDisk’s free scan opens the same folders with the same labels, Safe, Review and Leave it, and moves selections to the Trash first. It shows protected system and account folders but does not offer them for removal, which is the boundary this guide recommends you keep by hand as well.