Occasionally, users may find that after installing the latest version of iTunes on their Mac an error message appears reporting that the copy of iTunes is unusable and must be reinstalled. Resolving the issue requires removing all iTunes components from your machine and reinstalling a fresh download. Read on to see how.
When faced with the error message that states the current copy of iTunes is unusable and must be reinstalled, first quit iTunes. Then, remove all copies of the "iTunes.dmg" file that exist on your Mac. Do a Spotlight or Finder search to be sure there is not an extra downloaded file somewhere on your system.
Next, remove iTunes and all its components from your machine:
- Be sure iTunes is not running.
- Navigate to your Applications folder, find the iTunes application, and drag it to the Trash (or Command + Delete).
- Open Activity Monitor (Applications > Utilities).
- Locate iTunes Helper in the process list and choose, Quit Process. Click Quit again.
- Quit Activity Monitor and open System Preferences.
- Click on Accounts and select your user Account. Click Login Items in the main window and select iTunes Helper.
- Click the minus (-) button to remove it and quit System Preferences.
- From the Finder menu bar, choose Go > Go To Folder and type: /System/Library/Extensions
- Click Go, locate the file: AppleMobileDeviceSupport.pkg, and drag it to the Trash (this file may not exist on systems running Mac OS X 10.6 or later).
- Remove any other file with iTunes in the title that has the (.pkg) extension.
- Other files may also exist in your user Library folder that need to be deleted. Navigate to username > Library and find and delete the following preference files:
- Navigate to username > Library > Preferences > ByHost and find and delete any preference files containing "com.apple.iTunes".
- Restart your Mac and empty your Trash when it reboots. iTunes should be fully removed.
Lastly, get the latest version of iTunes directly from Apple, download, and install it.