OS X: Cross-platform filename best practices and conventions

Learn about best practices and conventions for creating cross-platform filenames.

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Most of the time, you shouldn't see any issues sharing files with other drive formats and operating systems. For example, OS X also automatically appends file extensions to your file names to improve compatibility. There may be special cases though, where you need to consider how you name your files. Consider the following best practices if you plan to share files from your Mac with other operating systems.


Avoiding "special" characters

The most conservative file naming conventions provide the most cross-platform compatibility. This ensures that your filenames work with different operating systems and disk formats, such as Windows, Mac OS X and other UNIX operating systems. File names can also be an important consideration when you transfer files via the Internet, where you may not be certain what computer platform your files may be stored on, even if temporarily.


For greatest compatibility, avoid using "special" non-alphanumeric characters. These characters are sometimes reserved for special purposes depending on the operating system.


Avoid Example characters Reasons
File separators

: (colon)
/ (forward-slash)
\ (backward-slash)

You should avoid using colons and slashes in the names of files and folders because some operating systems and drive formats use these characters as directory separators. Consider substituting an underline (_) or dash (-) where would normally like to use a slash or colon in a filename.
Non-alphabetical and non-numerical symbols ¢™$® Non alphanumeric characters may not be supported by all file systems or operating systems, or may be difficult to work with when exported to certain file formats such as EDL, OMF, or XML.
Punctuation marks, parentheses, quotation marks, brackets and operators . , [ ] { } ( ) ! ; " ' * ? < > | These characters are often reserved for special functions in scripting and programming languages.
White space characters such as spaces, tabs, new lines and embedded returns.   Although OS X and Mac OS formatted disks support spaces in filenames, certain processing scripts and applications may not recognize these characters, or may treat your files differently than expected. Consider substituting an underline (_) or dash (-) where you would normally use spaces.


Restricting filename length

Although current file systems such as HFS+ (used by Mac OS X) allow you to create filenames with a 255-character limit, you may want to limit your filename length if you intend to transfer your files to other operating systems. Non-english, multiple-byte characters such as some Japanese, Chinese, and Korean symbols may actually take up to the equivalent of nine English characters to store on some file systems. This should be considered when attempting to create longer names.


Using filename extensions

OS X and other operating systems can use file extensions when determining which application to open a file with, or what method of transfer to use for a network transfer. If you intend to transfer your media or project files to something other than a Mac, consider leaving the standard file extensions OS X automatically appends to file names. Some common file extensions include .mov (MPEG file), .xml (XML file), .zip (ZIP compressed archive file), .aif (AIFF audio file), .wav (WAVE audio file), .psd (Photoshop graphics file), .jpg (JPEG graphics file), and .png (TIFF graphics file).


Adding times and dates to filenames

If you add dates to a filename, avoid using special characters like a slash (/) to separate date elements, since that may be interpreted as a file separator on some operating systems. Consider using an underline or dash as a separator instead.


Using multiple volumes

If you have multiple hard disks, partitions, or volumes connected to your computer, avoid using similar names for these items. Names that are too similar may cause problems for certain applications. Each volume should have a name that doesn’t contain the entire name of another disk or partition.

  • Avoid filenames such as: “Media” and “Media 1”
  • Create filenames such as: “Zeus” and “Apollo” 

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