It is common for Mac users to encounter issues where certain files seem to be missing or not showing up when browsing in Finder. These “hidden” files are not actually missing, but rather have been set to be invisible by default on Mac OS. While this helps prevent clutter and reduce confusion for novice users, it can be frustrating when you need to access a file that you know exists, but you can’t seem to find it. The good news is that with just a few simple steps, you can easily view and access these hidden files on your Mac.
File Systems on Mac
The two main file systems used on Mac computers are HFS+ (also known as Mac OS Extended) and APFS (Apple File System).
HFS+ is the legacy file system that was used on Macs for over 20 years until it was replaced by APFS. It uses a hierarchical structure to store files and folders, and supports features like permissions, compression, encryption, journaling and multi-fork files. HFS+ is reliable and well-tested but has limitations like poor scaling beyond 2TB volumes and inefficient use of storage space on solid state drives.
APFS is the new default file system introduced in 2017 with macOS High Sierra. It was designed for modern storage needs like solid state drives and has improved support for encryption, file cloning, snapshots, space sharing and crash protection. APFS scales better to large volumes and optimizes storage on SSDs. It also has a 64-bit architecture, allowing support for 9 quintillion files on a single volume. Overall, APFS is faster, more reliable and advanced compared to the aging HFS+ file system.
What are Hidden Files?
Hidden files on Mac are system files that are not visible in Finder by default. They typically start with a period “.” and are used by macOS and applications to store configuration data, cache files, logs, and other information that doesn’t need to be accessed regularly by users.
Some examples of common hidden files and folders on Mac include:
- .DS_Store – stores finder display information like icon position
- .localized – stores localized resources for apps
- .Trash – stores files deleted from the Trash before emptying it
- .Spotlight-V100 – indexes files for Spotlight searching
- .hotfiles.btree – stores hotfile tracking data for Quick Look
- .fseventsd – stores file system event logs
These hidden system files allow macOS and apps to function properly in the background. Users don’t need to access them directly in most cases. But sometimes it can be useful to view hidden files for troubleshooting or cleaning out old logs/caches.
Why Files Get Hidden
There are a few main reasons why files may become hidden on your Mac:
The dot underscore convention – Any file or folder name that begins with a dot “.” or underscore “_” is automatically hidden in macOS and most Linux systems. This convention allows developers and applications to store configuration and settings files in a hidden place that doesn’t clutter your file browsing. For example, “.DS_Store” files created by Finder will be hidden.
Manually hiding files – Users can manually hide files by adding a dot or underscore to the start of the name in Finder or using a terminal command like “chflags hidden filename”. You may have hidden some files yourself and forgotten about them.
Backup files – Apps like Time Machine or backup utilities will often create hidden copies of files so they don’t interfere with your main files. These will usually have names like “filename.ext.cpgz”.
Cached files – Apps and websites use hidden cached files to speed up performance. For example, Safari stores cached website data in a Hidden Caches folder.
Third-party apps – Some apps hide their data files and internal resources in the background. For example, Adobe apps tend to hide files it uses to run smoothly.
Stray system files – Occasionally some macOS system files can become hidden if permissions get changed or other issues occur. For example, swap or sleep image files.
So in summary, the leading dot underscore convention, manually hiding files, backups, caches, apps hiding data, and stray system files are the main reasons you may notice some hidden files on a Mac.
Viewing Hidden Files
There are a couple ways to view hidden files on a Mac. The easiest is to use Finder. Open a Finder window, click the Finder menu, and select “Preferences.” Check the box for “Show hidden files” to enable viewing of hidden files in Finder. This will make hidden files visible across your entire system (Source).
You can also view hidden files using Terminal. Open the Terminal app and type “defaults write com.apple.Finder AppleShowAllFiles YES” and press enter. Then type “killall Finder” to restart Finder and apply the change. Now hidden files will be visible in Finder. To reverse this, type “defaults write com.apple.Finder AppleShowAllFiles NO” (Source).
Using Terminal to view hidden files gives more granular control, as you can choose which folders to show hidden files in rather than applying system-wide. The ls command with the -a flag will show hidden files in a specific folder. For example, “ls -a /Users/YourUsername” will list all files, including hidden ones, in your home folder.
Unhiding Files
There are a few different ways to unhide files on a Mac. The easiest way is through Finder. Simply open a Finder window, press the Shift + Command + . keyboard shortcut, and any hidden files will become visible (eshop.macsales.com). You can then right click on a hidden file or folder and select “Make Visible” to unhide it.
You can also use the Terminal app to unhide files. Type in the command “defaults write com.apple.finder AppleShowAllFiles YES” and press enter. This will immediately make all hidden files visible in Finder (avast.com).
Finally, utilities like TinkerTool give you granular control over which hidden files get unhidden. You can toggle visibility for specific system files that macOS hides by default. This helps avoid unhiding unnecessary clutter while revealing the specific hidden items you need (discussions.apple.com).
Best Practices for Managing Hidden Files
Here are some recommendations for properly managing hidden files on your Mac:
Be selective about which files you hide – only hide sensitive personal files that need to be kept private. Don’t hide system files needed for your computer to operate properly.
To hide a file or folder, use the Shift + Command + . keyboard shortcut. This will toggle the visibility on and off. Refer to this guide for step-by-step instructions.
Be careful not to accidentally hide important folders like Documents or Downloads. You may lose access to files you need.
Keep a list somewhere of any hidden files or folders so you remember what you hid. Or use labels or tags to indicate hidden status.
Back up your hidden files separately, in case you need to access them again later or have trouble unhiding.
Watch for issues opening apps or accessing files, as accidentally hiding system files can cause problems. If issues arise, unhide files systematically to identify the cause.
Use additional encryption like FileVault for your most private hidden folders, don’t rely on just hiding files.
Educate yourself on securely deleting sensitive files you no longer need rather than just hiding them.
Keep your Mac’s operating system up to date to ensure proper security and performance when managing hidden files.
Troubleshooting Hidden Files
Sometimes there are issues that prevent you from being able to view hidden files on your Mac. Here are some troubleshooting tips if you are having problems accessing hidden files:
If the keyboard shortcut Command+Shift+Period does not work, try restarting your Mac. This refreshes the file system and can resolve shortcut issues.
Make sure you do not have any apps or windows active when using the keyboard shortcut. The shortcut will not work if you are currently typing in a document or have an active app window.
Check your Finder preferences to ensure “Show Hidden Files” is enabled under the Advanced settings. Sometimes this gets toggled off which hides hidden files.
If some hidden files are stuck and won’t unhide, try revealing them in Terminal using the chflags nohidden /path/to/file command (from apple.stackexchange.com).
For permissions issues with accessing hidden files, you may need to repair disk permissions in Disk Utility. This ensures your user account has proper access.
As a last resort, try resetting the Finder by relaunching it. Press Command+Option+Esc, select Finder and click Relaunch.
Security Risks
Hidden files can pose potential security risks in certain situations. For example, malware programs may create hidden files or folders to avoid detection. According to Charjenpro, some hidden files like encryption keys or authentication tokens may contain sensitive information that could be exploited if accessed by unauthorized users.
There have also been cases of malware infecting USB drives and turning normal files into hidden .exe files when plugged into a Mac, as noted in an Apple forum discussion. This demonstrates the need for caution when plugging in external devices of unknown origin.
While hidden files themselves are not inherently dangerous, the potential for malware to exploit them means users should be careful when revealing and handling hidden files. Scanning external drives with antivirus software can help detect malware before it can infect your system.
Conclusion
Understanding why you might not see all files on your Mac is important for properly managing and accessing your data. The Mac operating system hides certain system files and folders by default for performance and security reasons. User action like adding a “.” prefix can also hide files in the Finder. While hidden files usually don’t need to be accessed, you can view them by changing Finder preferences or using the Terminal. Unhiding files is also possible but should be done with caution to avoid messing up your system. Best practices are to avoid unnecessarily accessing system files, understand the implications of viewing hidden files, and make backups before experimenting. Overall, the Mac file system is designed to balance usability with underlying complexity. Knowing how to view hidden files when needed, while generally keeping them hidden, allows you to get the most out of your Mac.
