Are you unable to Fix Internal File System Error in Mac OS X ? Here is the complete guide to fix the error and if any data is lost due to it you can recover it now. The internal file system error may occur and the time of upgrading the operating system to the newer version or if the drive volume where the operating system is installed has been corrupted. Some of the other reasons are the virus infection, dislocation of the system files mistakenly done by the user. To fix internal file system error in Mac OS X you have to either reinstall the Mac OS X or upgrade the operating system properly. Now when the error is fixed you will be able to log in to the Mac system but you will notice that all the files that were saved in the Mac drive are lost. You can get the files back by using the time machine backup utility or else when it fails you can try the Mac data recovery software. Install the software after you fix internal file system error in Mac OS X and scan the Mac drive to recover all the files.