5 folders on macOS you should not touch

MacOS has a complex directory structure and lots of directories integrated into each other. MacOS settings by default have many folders that are not very familiar to users. Therefore, most users never need to touch these files.

Apple hides some directories for a reason. Cluttering these folders can make the system unstable, lose data, or worse, prevent your Mac from booting. The following article will show you places where most users should not touch the macOS file system.

1. Language files and folders

Mac applications come with language files for every language they support. When you switch the Mac system language, the application will switch to that language immediately.

To view the language files of an application, right-click it and select Show Package Contents from the context menu. The path will look like this:

 AppName.app/Contents/Resources/Lang.lproj 

Removing language files for third-party applications is easy through Terminal. But for default macOS applications, you need to disable the System Integrity Protection feature . Although there are lots of advice on the Internet suggest that you delete language files for more disk space, but the amount of space you save can't compensate for the associated risks you can encountered.

A quick scan with CleanMyMac indicates that users will get about 520MB of disk space, by deleting these files. The result may be different in your case, but it is very unlikely that you will save more than a few gigabytes. In addition, you must redo the steps, after each macOS upgrade.

When you delete language files, you cannot predict which applications will fail or cannot work. In the worst case, you will have to reinstall the application. In addition, older versions of programs such as Microsoft Office and Adobe applications may not work properly or cannot be updated. Therefore, it is best to ignore language files and directories. Instead, see tips for freeing up space on other Macs to do this better.

2. Hide / private / var directory

MacOS creates a number of cache files related to users and systems to speed up the system. The cache and temporary data are in / Library / Caches, under user control. You can clear this cache manually without any third-party tools.

But these cache files in the system directory are fully managed by macOS. You can't even see them. Sometimes the items in these folders can occupy a large amount of disk space. So, you may wonder if it is safe to delete the contents of / private / var / folders .

Location of / private / var / folders

The easiest way to find the / private / var directory is through the Finder Go to Folder menu. Press Cmd + Shift + G to open the Go to Folder box and enter / private / var / folders. A new Finder tab will open immediately.

To open the location of temporary files and system cache files, launch the Terminal window and enter the following:

 open $ TMPDIR 

You will see a folder name with two characters with long and seemingly random subdirectories. When you navigate the directory tree, explore these three directories. Directory C represents Cache, while T is for temporary files. User files are in directory 0 .

Issues related to / private / var / folders

A quick scan with OmniDiskSweeper shows that the size of / private / var / folders is 1GB and / private / var is about 4GB. The size of these directories may be different for each system, but not too large. If these folders account for more than 10GB, they are very worrying.

You should not try to delete manual files from any / private / var directory , even if they are too large. Doing so may damage important macOS files, corrupted document data and prevent Macs from booting or operating as expected. Then you will be forced to reinstall macOS from scratch.

To safely delete these files, exit all applications and select Apple Menu> Shut Down . When you reboot your Mac, activate the built-in cache deletion mechanisms. This will delete unnecessary content, cache and temporary entries in / tmp, / private / var and / private / var / folders.

If for some reason these files cannot be deleted, restart your Mac in Safe Mode, because macOS implements additional built-in mechanisms to remove cache and temporary files in this mode. Then reboot into Normal mode as usual and check your available disk space.

Other important directories in / private / var

Regarding disk space, there are several other directories that you should not touch:

1. / private / var / db: Includes a variety of data files and macOS configuration. These include Spotlight database, network configuration file and more.
2. / private / var / VM: Contains swap and sleep image files. If you put Mac into hibernation, this folder will take up more than 5GB of disk space.
3. / private / var / tmp: Another temporary file directory.

3. System Library folder (System library)

The macOS file system contains many Library folders . This is due to the design, and although there are many similarities in the content of the Library folder, each folder has a different role in the file system on macOS. You will find three Library folders:

1. /Thư viện
2. / System / Library
3. ~ / Library

Main directory and System Library have a comprehensive range. Their content supports all aspects of the system. The System Library folder contains the files that macOS needs to operate. Only the OS has the right to modify its data and only system-level events affect them. There is no reason for you to touch any content in this directory.

4. User Library folder (User library)

The Library folder inside the main directory is the personal library for your account. Here, macOS stores the system, third party support files and options. It also includes mail settings, Safari bookmarks, history, calendar data and more. The Library folder also includes folders that need to be cleaned regularly. However, not all folders are safe if you touch them.

1. Show ~ / Library folder on macOS Sierra

~ / Library / Application Support

In this directory, both third-party applications and systems store support files, usually in sub-directories named after the application. They contain registration data and even store saved application data, used in a specific session. Do not delete the contents of Application Support files directly . Instead, use the application called AppCleaner to delete the support files that come with the application.

~ / Library / Preferences

This folder contains all the optional data for default applications and third-party applications. Again, do not delete the contents of the Preferences folder ; otherwise an application will return to its default state or be corrupted. AppCleaner will manage options while uninstalling the application.

~ / Library / Mobile Documents

This is the actual location of iCloud folder. Documents, application options files, iOS application data and many other things are in this directory. You should not move, rename or delete it. It is also a folder that takes up much disk space, if you use iCloud. Delete files you don't need from iCloud Drive to reduce the size of this file.

~ / Library / Containers

This section contains support files, cached data and temporary files for applications you have downloaded from the Mac App Store. Because apps on the App Store are sandboxed, they cannot write data anywhere on the system. Again, do not delete the contents of this directory. If the Containers folder takes up a lot of disk space, reinstall the affected application.

5. Folder hidden in the Home folder

When you press the Cmd + Shift + Period key in the Finder, you will see many files and subfolders in the Home folder hidden from view. Different macOS technologies and applications store their data in these folders to make the Mac work process smoother. You should not modify or delete any of the following directories:

1. .Spotlight-V100: Focus metadata for each mounted drive. Processes mdworker use this metadata to update Spotlight search.
2. .fseventsd: A log file of FSEvents recorded by fseventsd initialization process . It monitors file system-related events, such as file creation, modification, deletion, and more. Time Machine uses this data to handle backups in the background.
3. .DocumentRevisions-V100: The macOS version database is used by the application to save and retrieve different versions of the document.
4. .PKInstallSandboxManager: Used for software updates and sandboxes.
5. .PKInstallSandboxManager-SystemSoftware: Used to update the system software.
6. .Trashes: Trash folder in each mounted drive.

Confusing these directories is dangerous, as doing so may damage your apps, documents and macOS. While most Mac users don't have to worry about these folders, you can be curious and start exploring these directories when you have problems with disk space.

Creating backups is essential. If you lose any data, you can recover data relatively easily.

Good luck!

See more:

1. Instructions for using OS X's Wi-Fi channel scanning feature
2. Lock iPhone, iPad, Mac devices remotely when you lose your device
3. How to access more than 40 "secret" background images on OS X Mavericks