In case of system malfunction, startup disk feature of Mac Utility enables you to make a virtual drive for restoring your system to previous working state. It includes creating startup disk through Snow Leopard installer that Mac would restore while installing new OS.
You can create restore disk by following underwritten steps:
1) Clean your hard disk and system folder.
2) Delete unused extensions, empty folders and unwanted files.
Do remember to create a backup of your data before deleting files and now extract image file from Mac OS X installation DVD and convert it to *.dmg file before moving it to external drive such as USB drive.
3) Attach your USB disk to system and wait until it appears and then launch Disk Utility then select USB drive.
4) Click on Restore tab and select image file that you have extracted on ’source’ field and then drag external disk to ‘destination’ field. You must create a partition, otherwise the process would remove all data from your hard drive.
5) Select USB drive and the partition. Choose Restore. When the restore process completes successfully, open System Preferences.
6) Open start-up disk application and select restore drive with.
7) Restart the system and operating system would start to install.
This is a very useful method, but in the case when the back up has not being created and the process fails, critical data loss situations occur. In these cases, you need to perform Erase and Install, installation of Mac OS X and then perform Mac data recovery.
Mac File Recovery is best possible using third-party applications, known as Mac file Recovery Software. They have simple graphical user interface to provide ease of use and extensive scanning techniques to ensure absolute recovery in all cases of data loss. With read-only and non-destructive conduct, tools are completely safe to use.