Application Support

Contains all app-specific data and support files. These are the files that your app creates and manages on behalf of the user and can include files that contain user data.

By convention, all of these items should be put in a subdirectory whose name matches the bundle identifier of the app. For example, if your app is named MyApp and has the bundle identifier com.example.MyApp, you would put your app’s user-specific data files and resources in the ~/Library/Application Support/com.example.MyApp/ directory. Your app is responsible for creating this directory as needed.

Resources required by the app to run must be placed inside the app bundle itself.

Assistants

Contains programs that assist users in configuration or other tasks.

Audio

Contains audio plug-ins, loops, and device drivers.

Autosave Information

Contains app-specific autosave data.

Caches

Contains cached data that can be regenerated as needed. Apps should never rely on the existence of cache files. Cache files should be placed in a directory whose name matches the bundle identifier of the app.

By convention, apps should store cache files in a subdirectory whose name matches the bundle identifier of the app. For example, if your app is named MyApp and has the bundle identifier com.example.MyApp, you would put user-specific cache files in the ~/Library/Caches/com.example.MyApp/ directory.

ColorPickers

Contains resources for picking colors according to a certain model, such as the HLS (Hue Angle, Saturation, Lightness) picker or RGB picker.

ColorSync

Contains ColorSync profiles and scripts.

Components

Contains system bundles and extensions.

Containers

Contains the home directories for any sandboxed apps. (Available in the user domain only.)

Contextual Menu Items

Contains plug-ins for extending system-level contextual menus.

Cookies

Contains data files with web browser cookies.

Developer

Contains data used by Xcode and other developer tools.

Dictionaries

Contains language dictionaries for the spell checker.

Documentation

Contains documentation files and Apple Help packages intended for the users and administrators of the computer. (Apple Help packages are located in the Documentation/Help directory.) In the local domain, this directory contains the help packages shipped by Apple (excluding developer documentation).

Extensions

Contains device drivers and other kernel extensions.

Favorites

Contains aliases to frequently accessed folders, files, or websites. (Available in the user domain only.)

Fonts

Contains font files for both display and printing.

Frameworks

Contains frameworks and shared libraries. The Frameworks directory in the system domain is for Apple-provided frameworks only. Developers should install their custom frameworks in either the local or user domain.

Internet Plug-ins

Contains plug-ins, libraries, and filters for web-browser content.

Keyboards

Contains keyboard definitions.

LaunchAgents

Specifies the agent apps to launch and run for the current user.

LaunchDaemons

Specifies the daemons to launch and run as root on the system.

Logs

Contains log files for the console and specific system services. Users can also view these logs using the Console app.

Mail

Contains the user’s mailboxes. (Available in the user domain only.)

PreferencePanes

Contains plug-ins for the System Preferences app. Developers should install their custom preference panes in the local domain.

Preferences

Contains the user’s preferences. You should never create files in this directory yourself. To get or set preference values, you should always use the NSUserDefaults class or an equivalent system-provided interface.

Printers

In the system and local domains, this directory contains print drivers, PPD plug-ins, and libraries needed to configure printers. In the user domain, this directory contains the user’s available printer configurations.

QuickLook

Contains QuickLook plug-ins. If your app defines a QuickLook plug-in for viewing custom document types, install it in this directory (user or local domains only).

QuickTime

Contains QuickTime components and extensions.

2012-11-9  The Library folder at the root level of your hard drive is a public ‘library’ of data that is required for all users of the Mac. The Library folder within the System folder is critical for the operation of your Mac. Don’t ever remove, rename or otherwise move this directory in any way. Leave it alone! 2020-4-6  Before going ahead with the steps to Access the Hidden Library Folder on your Mac, you need to be aware that /Library Folder contains important Data and Files related to Mac User Accounts. Hence, make sure that you are accessing the Library Folder for a good reason and you do know as to what you are trying to achieve. Mac system drive library folder. Apple hides the Library folder by setting a file system flag associated with the folder. You can toggle the visibility flag for any folder on your Mac; Apple just chose to set the Library folder's visibility flag to the off state by default. Here's how to change it. So, your Mac is running out of storage. You try to figure out what’s taking up your disk space by clicking the Apple logo on the top-left of the screen, selecting About This Mac, and hitting the Storage tab. To your surprise, you see a yellow bar representing “System” that seems to occupy way more space than you think it should.

Screen Savers

Contains screen saver definitions. See Screen Saver Framework Reference for a description of the interfaces used to create screen saver plug-ins.

Scripting Additions

Contains scripts and scripting resources that extend the capabilities of AppleScript.

Sounds

Contains system alert sounds.

StartupItems

(Deprecated) Contains system and third-party scripts and programs to be run at boot time. (See Daemons and Services Programming Guide for more information about starting up processes at boot time.)

Web Server

Contains web server content. This directory contains the CGI scripts and webpages to be served. (Available in the local domain only.)