# What Is Safe to Delete in the Mac Library Folder?

> Folder by folder: what lives in ~/Library on a Mac, which parts rebuild themselves, which hold your data, and the right way to shrink each one.

Canonical: https://bytesweep.app/answers/mac-library-folder-what-to-delete.html
Last updated: 2026-11-04

## What is safe to delete in the Library folder on a Mac?

Folder by folder: what lives in ~/Library on a Mac, which parts rebuild themselves, which hold your data, and the right way to shrink each one.

- By [Shajeen Ahamed](https://bytesweep.app/about.html#author)
- Updated 4 November 2026
- Steps checked against Apple's documentation

**Short answer**

Very little, by hand. `~/Library/Caches` and `~/Library/Logs` are rebuilt by the apps that wrote them, so clearing them with those apps closed is low risk. Application Support, Containers, Group Containers, Preferences, Mail, Messages and Mobile Documents hold real data: shrink those from inside the app that owns them, never by dragging folders to the Trash.

### Which Library folder is this about?

A Mac has three, and only one of them is yours to tidy:

- **`~/Library`**, inside your home folder. Your apps' data, caches and settings. This page is about this one.
- **`/Library`**, at the top of the disk. Shared by every user: fonts, printer drivers, launch daemons, audio plug-ins. Change it only to remove something you installed.
- **`/System/Library`**. Part of macOS, on a sealed, read-only volume. Nothing in it can be deleted, by you or any cleaner. [How the sealed system volume works](https://bytesweep.app/blog/macos-sealed-system-volume.html).

To open yours, hold Option and choose Go, Library in Finder, or press Command-Shift-G and type `~/Library`. To see which parts are big, run `du -sh ~/Library/* 2>/dev/null | sort -h | tail -15` in Terminal, or follow [how to see folder sizes](https://bytesweep.app/answers/see-folder-sizes-on-mac.html).

### Folder by folder: what can go?

| Folder in ~/Library | What it holds | Delete by hand? | The right way |
| --- | --- | --- | --- |
| Caches | Data apps can download or work out again: thumbnails, web caches, package caches | Yes, with the app closed | Quit the app, delete its folder inside Caches. It refills as you use the app. |
| Logs | Diagnostic logs and crash reports | Yes | Delete old files; keep recent crash reports if you are chasing a bug. |
| Saved Application State | Which windows each app had open | Yes | Apps reopen with no windows restored. Small, rarely worth it. |
| Developer | Xcode's DerivedData, Archives, simulators and device support files | Partly | DerivedData rebuilds; Archives do not. See [Xcode storage cleanup](https://bytesweep.app/xcode-storage-cleanup.html) . |
| Application Support | Each app's own data: databases, libraries, downloaded content; also iPhone backups under MobileSync/Backup | No | Remove the app with its leftovers, or delete content inside the app. iPhone backups: Finder, your iPhone, Manage Backups. |
| Containers | The private data of sandboxed apps, App Store apps among them; Docker's disk image lives here too | No | A container is the app's data, not a copy. Delete inside the app, or uninstall it. Docker: [shrink it from Docker](https://bytesweep.app/docker-disk-space-mac.html) . |
| Group Containers | Data shared between an app and its extensions, or between apps from one developer | No | Same as Containers. Office, messaging and password apps keep real data here. |
| Mobile Documents | Your iCloud Drive, as stored on this Mac | No | Deleting here deletes from iCloud on every device. To free space, right-click a file in iCloud Drive and choose Remove Download. |
| CloudStorage | Dropbox, OneDrive, Google Drive and Box files on recent macOS | No | Same rule: use the provider's "make online-only" option, never delete. See [Google Drive and OneDrive on a Mac](https://bytesweep.app/blog/google-drive-onedrive-mac.html) . |
| Mail | Downloaded mail and attachments | No | Delete mail in Mail; in Mail settings, choose which accounts keep copies on the Mac. |
| Messages | Your message history and every attachment | No | Messages settings, Keep messages; or System Settings, General, Storage, Messages to review big attachments. |
| Preferences | Every app's settings, as .plist files | No | Tiny. Deleting one resets that app; deleting many resets the Mac's apps to factory settings. |
| Keychains | Saved passwords, keys and certificates | Never | Manage passwords in the Passwords app or Keychain Access. |

### Why did the Caches folder fill up again?

Because that is what a cache is for. A browser, Spotify or Xcode keeps a cache so it does not have to download or compute the same thing twice; empty it and the app is a little slower for a while as it rebuilds what you use. Clearing caches is worth doing when one app's cache has grown far past what it needs, such as a package manager that keeps every version it ever downloaded, or an app you have stopped using. Clearing all of them every week gains little and costs speed.

### What goes wrong when people delete Library folders by hand?

- **Lost app data.** A sandboxed note-taking or drawing app may keep its whole database in its Container. Deleting the container deletes the notes, with no copy anywhere unless the app syncs.
- **iCloud deletions.** Removing files from Mobile Documents or CloudStorage is a delete, not a local clean-up, and it reaches every device signed in to the account.
- **Broken apps.** Deleting an app's Application Support folder while the app is open can corrupt its database, and many apps then start as if new.
- **Nothing gained.** Preferences, Saved Application State and most Logs are tiny. The space is nearly always in four places: Application Support (backups and app content), Containers (Docker, sandboxed apps), Developer (Xcode) and Caches.

If a folder is big and you do not know what it is, look it up by its name (it usually ends in the app's bundle identifier, such as `com.docker.docker`) before you remove it.

### Can an app sort this out for me?

That is most of what a Mac cleaner should do: tell you what a folder is before you delete it. Bytesweep reads ~/Library and the developer folders, names each item, and rates it **safe**,**review first**or**keep**. Its rules never clean your personal or system folders, iCloud files are only offered for removal from this Mac once macOS reports them fully uploaded, and what you clean is kept on the disk for 7 days so Undo puts it back. Commands macOS runs itself, such as deleting local Time Machine snapshots, cannot be undone, and the app says so first. It is free to try for 3 days; cleaning needs a $29.99 licence, once per computer. [How Bytesweep decides what is safe](https://bytesweep.app/how-it-works.html).

### Sources

Read on 4 November 2026. If something here has changed, write to [support@bytesweep.app](mailto:support@bytesweep.app) and it will be corrected.

- [Apple, Free up storage space on your Mac](https://support.apple.com/guide/mac-help/free-up-storage-space-sysp4ee93ca4/mac)
- [Apple, What is System Data on Mac storage](https://support.apple.com/en-us/102624)

### Keep reading

- [**What is System Data on a Mac**](https://bytesweep.app/mac-system-data.html)
- [**How do I see folder sizes on a Mac?**](https://bytesweep.app/answers/see-folder-sizes-on-mac.html)
- [**How Bytesweep decides what is safe to delete**](https://bytesweep.app/how-it-works.html)
- [**All answers**](https://bytesweep.app/answers/)

### See what is filling your disk, and why.

Bytesweep is free to try for 3 days on [Mac](https://bytesweep.app/mac.html), [Windows](https://bytesweep.app/windows.html) and [Linux](https://bytesweep.app/linux.html). Cleaning needs a licence: $29.99 once per computer, no subscription.

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