Unable to access and process any data on Mac due to OS X Lion no mountable file systems error? As we all know file system is needed to mounted properly in order to access any data on Mac, but sometimes it has been seen that HFS file system goes unexpectedly unmountable on Mac due to several reasons ans thus users are unable to access their important Mac files. Well, this very hazardous and annoying error OS X Lion no mountable file systems can be consequences of some common corruption issue like virus attack, abrupt system shutdown, catalog corruption, partitioning error, hardware malfunctioning, problem in Operating System and many more. Anyway, it is quite frustrating as well as disastrous situation for any Mac users and needed to shorted out at the earliest. In order to fix this issue completely on your Mac system you will need to take the help of Disk Utility. It is an inbuilt utility for Mac users and able to fix OS X Lion no mountable file systems easily and conveniently. As far as the matter of your inaccessible Mac files are concern, with using Mac Data Recovery Software you can effectively recover any deleted, corrupted, inaccessible or formatted data easily on Mac. therefore it is recommended to use Mac Data Recovery Software to rescue corrupt files on Mac after OS X Lion no mountable file systems error.