Are you getting Macintosh blue screen at startup ? This is pretty rare situation on a Mac system but if you are facing it then it is quite a serious problem. The Mac will not boot up as the Mac OS X will not load in the memory. The main cause of Macintosh blue screen at startup can be that there is some issue with the start up disk where the Mac operating system files are stored. May be the file system has been corrupted or there can be virus infection which leads to corruption of Mac OS X file. If the issue is related with the hard drive then you can deal with the disk utility that is in built in the Mac. When the virus infection is severe then it is better to format the drive and then reinstall the Mac operating system. By doing this you will fix Macintosh blue screen at startup but several important files will also get lost. You can recover them if you have set up the Time Machine backup earlier. IF the time machine fails, the last option is to try a recovery tool. The Mac data recovery software will scan the Mac drive and show the results of that. You can then select the files you require and save them in the desired location. You can recover lost data after fixing Macintosh blue screen at startup in a hassle free manner.