"Keys out of order mac OS X" error message is displayed by the disk utility when the found keys are not sorted properly. As the directory is used to store catalog node ID of files and folder which is very important for accessing file on Mac system thus corruption in directory key is directly responsible for the accessibility of your files. In such situation even when users try to repair their inaccessible files using Disk Utility Keys out of order Mac OS X error message is displayed on the screen. The best way to resolve this problem is to execute FSCK command. It is basically the command based version of disk utility. In order to do so, go to single user mode and then run the FSCK command on the terminal. While doing so you can easily fix Keys out of order mac OS X error for sure but your lost files can be retrieved. In order to restore your lost files on Mac you will need to use third party Mac Data Recovery Software. It is very effective and able to recover all the lost or corrupted file on Mac. therefore it is recommended to use Mac data Recovery Software in order to recover all your files lost due to Keys out of order Mac OS X error.