If you are unable to access the stored data and your Mac is showing all signs of trouble, then it is an indication for hard drive data recovery Mac. It is suspected that there is some sort of problem with the hard drive and there is need to repair the drive using Apple's Disk Utility. For that you need to repair permission settings that can be helpful at times. Before proceeding further, just check out for a backup. If there is one, it can easily resolve the issue for Hard Drive Data Recovery on Mac. There can be various reasons why this issue arises before mac users such as logical corruption, improper partition, formatting of the drive etc. If you do not have an advanced knowledge about Macintosh OS X, then there is no point trying Disk utility which is an inbuilt tool that can be used for repairing corruption to overcome Hard Drive Data Recovery Mac. Therefore it is better to use Mac data recovery software that is suitable for restoring hard drive data on Mac.