Are you searching for the topic disk utility no mountable file systems ? Mac uses the hfs + file system to manage the hard drive data, the Mac OS X is also installed in the same partition drive. If you want to create a new partition or connect an y other drive it better be in this file system other wise you can encounter disk utility no mountable file systems error. There are also other reasons of this error like the file system gets damaged, catalog or header file is corrupted, the disk is not properly mounted. You can try to remount the drive but if you are still unsuccesful then you can use the disk utility which is capable of detecting minor errors and try to fix it. If the disk utility fails then you have to format the drive to fix disk utility no mountable file systems. You can recover lost data of formatted drive by using time machine or else use the Mac data recovery software. It performs a quick or deep scan as per your choice and then provide the preview. Select required files from the preview and the software will restore them instantly. The recovery process is so simple that you wil easily perform it. So fix disk utility no mountable file systems and download the software to recover Mac data.