You are frustrated by the fact that the Mac system does not start and you can not access any of the file that is saved in the Mac hard drive. You are searching for its cause and for the solution of it but you are not finding it. So now you have come to the right place where you will get the proper assistance for the fixing this and getting your files back. The Mac system does not start when the Mac OS X file is not loading from the start up disk to the memory. This can happen if the operating system files are corrupted or the startup disk itself is corrupted. In both cases you will have to reinstall the operating system however for the drive corruption you will have to format the drive first with the help of disk utility. You can get the lost files back by using the time machine backup. If the time machine does not work then use the Mac data recovery software which can scan the Mac drive throughly and show the results in few moments for performing the recovery. So resolve the Mac system does not start problem and use the software for data recovery.