When you are booting up your Mac system you are getting Mac wheel of death. The wheel is rotating endlessly and you are unable to access the home screen of the Mac and as of result your data stored in the Mac drive will be inaccessible. The main cause of Mac wheel of death is Mac OS X corruption. The reason of corruption could be abrupt system shut down, and inconsistency in the file system of Mac drive, virus attack, improper up gradation of the operating system or any unknown issue. The Mac OS X corruption can be resolved to by formatting the hard drive with the help of disk utility and then install the operating system. The issue of Mac wheel of death os now resolved but in the process all of the other data is also lost, don't worry as the files can be recovered by using the time machine utility. If it fails then you can try Mac data recovery software. The software has advance methods to scan your Mac hard drive and then the files you choose from the preview will be restored. You can download this effective software here and recover your data when Mac whhel of death is fixed.