Invisible files on Mac OS X come in two different flavors: Unix-style invisible files and Mac OS 9-style invisible files.
On Unix systems every file whose name starts with a full stop (e.g.,
.secret) is considered to be
invisible. Mac OS 9-style invisible files rely on a meta-data flag that is part of the HFS/HFS+/Mac OS X
Extended (Journaled) file system used by Mac OS X; these files can have any name.
Invisible files are simply files that are not usually displayed by the Finder and in the various file dialogs; in all other respects they are perfectly “normal” files.
Invisible files exist because they usually contain “operating system stuff” that it is a bad idea for the user to mess around with.
Mac OS 9 used invisible files for a number of purposes, but the major one that still affects Mac OS X installations today is its use of
Icon\r files. These files contain the custom icon for the folder in which they are placed. In other words, whenever you see a folder that has a non-standard icon, chances are that there will be an invisible
Icon\r file inside of it.
Unix systems make heavy use of invisible files for all kinds of purposes. A lot of configuration information is kept in invisible plain text files, such as
.cshrc, etc. Removing these configuration files can have disastrous effects and may even prevent your system from re-booting properly.
Many third-party unix applications, such as version control systems (git, mercurial, subversion, cvs, etc.) use invisible folders and files to maintain state information.
The most commonly used hidden files in Mac OS X are
Pretty much every folder on your hard disk is likely to contain a
.DS_Store file. Its use by Apple is largely undocumented, but it is commonly believed to contain Finder-related information about the other files in the folder that contains it. This appears to include at least positioning information (the location at which the icon appears in the Finder’s
as Icons view), what type of document each file represents, file comments, file color, etc. The main purpose of this file appears to be to boost the Finder’s performance when displaying the
folder contents to the user by acting as a “cache”.
.localized files appear to simply contain user language dependent data. This allows the Finder to display localized folder (and file?) names. A good example of this is the
Applications folder, which on the file system is called
Applications, but magically appears to the user with a localized name (e.g.
There are a number of reasons why you might want to get rid of some or all invisible files within a folder hierarchy:
All those hidden files can cause mayhem when used in a context other than with a Mac-only application on your own Mac.
For one thing if they make their way onto a non-Macintosh system, they may no longer be hidden and all those
.DS_Store files will pollute your folder hierarchy. The Finder is prone to putting a
.DS_Store file into
every directory that you look at, even if you only have a quick browse on a Windows NTFS volume. The
multi-platform CDs that you burn are also likely to have those files appear in them..
Worse than just polluting but not otherwise impairing non-Macintosh systems, invisible files may actually prevent
you from transferring files onto those systems in the first place. The so-called SMB remote file sharing with
Windows machines for instance is prone to “choking” on hidden
Icon\r files in particular. After transferring
10GB of data over the connection, you’ll suddenly be presented with an error message “
..\..\..\Icon could not
be found. Aborting.”
Many professional tools that have been migrated from other platforms (Unix, Windows, etc.) also simply do not know
about Mac OS X’s invisible files and this can produce all kinds of problems. Version control systems (such as
Subversion or CVS), for instance, will not ignore the hidden
.DS_Store files and will consider that the folder
has changed each time those files are updated (potentially each time you point the Finder at them!). Once they
are under version control, they can cause further mayhem especially in multi-user environments.
As mentioned before, the
.DS_Store files act as a cache for the Finder and if for any reason
(there appear to be plenty!) they get out of sync with the real contents of the folder, they can lead to stale
information about your files being displayed. Removing the
.DS_Store file will force the Finder to update its
information (you will however lose file comments, colors, positioning, etc information if you do this!).
It pays to be cautious when using this feature. We recommend that you:
(Please note that this feature is not available in File Multi Tool because of Mac App Store restrictions)
A Better Finder Attributes allows you to make all invisible files visible in the Finder. It does this by activating a “secret” Finder mode and without modifying any files, i.e. you needn’t worry about making irreversible changes to your file system simply by activating this mode.
Moreover, this functionality is not a “hack” that would make your Finder less stable, but it is a hidden feature developed by Apple engineers, presumably for their own convenience.
You can activate this mode by selecting
Show invisible files in the Finder in
Tools menu and later de-activate it using
Hide invisible files in the Finder.