Email, Messaging, & Video Calls Email How to Change Sounds in Mac OS X Mail by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on June 04, 2019 Email Yahoo! Mail Gmail Tweet Share Email Mac OS X Mail can announce new messages with a sound, and if you don't like the default chime, a different flourish is easily substituted. But what about the sounds used for "other" mail actions? Is there a way to change the sound played when a message is delivered successfully, for example, or when an error has occurred during mail retrieval? There is, albeit not in the Mac OS X Mail preferences. You have to dig a bit deeper. Due to the advanced nature of this change, please be extra careful with every step and create the initial backup before you change anything. Change Sounds Played for Other Mail Actions in Mac OS X Mail To change the sounds played for "other" Mac OS X Mail actions: Make sure you have AIFF versions of the sounds you want to be played (see below).With Mail open, Control-click on its Dock icon.Select Show In Finder from the menu.Shut down Mail.In Finder, while holding down the Option key drag and drop Mail next to itself, to create a backup copy (called "Mail copy" by default).Control-click on the original Mail icon.Select Show Package Contents from the menu.Open the Contents and then the Resources folders.Replace the desired sound file with your (identically named) version:Mail Sent.aiff — plays when a message has been delivered.No Mail.aiff — Mail has checked for mail, but nothing new has arrived.Mail Fetch Error.aiff — indicates the last attempt to retrieve mail was unsuccessful.Start Mail to hear your new sounds in action. Create AIFF Versions of Your Desired Mail Sounds If the sound you want to be played for a particular Mac OS X Mail actions is not yet in AIFF format (indicated by an ".aif" or ".aiff" extension), you can create an AIFF version with converter software: SoundConverter — the list of supported formats is long (free for files under 500KB).QuickTime Pro — any file QuickTime can play, the Pro version can save as a .aiff. Caution in Mac OS X 10.5 and Later In Mac OS X 10.5 (Mail 3) and later, applications that come with the operating system are signed by Apple. Editing them like you do when changing sounds or other resources breaks the signature and may prevent them from accessing keychain passwords. In Mail, you'd have to type your email account password anew each time.