A Mac OS X computer system might behave abruptly after you install any major Mac OS X update. In severe situations, the computer might fail to boot. To solve these problems, you might need to reinstall the operating system which deletes and causes data inaccessibility. If a valid data backup is not available in such situations, you will need to use a Data Recovery Mac software.
For instance, suppose you use a Mac OS X based computer system. You install a Mac OS X 10.4.5 or a security update. After this, when you try to boot the computer, you observe a blank grey or blue screen with no access to stored data. Alternatively, you might experience that the system pauses indefinitely at the Apple logo.
Solution
You should try solving system startup issues post installing Mac OS X updates by these methods:
Boot errors can occur due to corruption of cache and .plist files. Try deleting the files by starting the computer in Safe mode by holding ‘Shift’ key while startup
If the login or startup items are faulty, this might create issues while boot. You should boot the computer in safe mode, go to System Preferences through Accounts page and remove all the login items. You also need to check /System/Library/StartupItems and /Library/StartupItems folders to remove third-party items.
Remove third-party kernel extensions, if any, from /System/Library/Extensions by booting the computer in safe mode
Check the disk for consistency and repair it using Disk Utility. This will correct all the permissions and drive directory damage issues. For this, you need to boot the computer using Mac OS X installation CD or DVD. You can also try repairing the disk using fsck by booting in single-user mode
Try disconnecting all the ethernet cables
Try duplicating the system behavior after disconnecting external devices, such as USB, FireWire etc. and internal cards, such as ExpressCards, PCI cards etc.
You should uninstall the latest updated installed and revert to the last Mac OS X version
If the issue persists, perform clean install of Mac OS X and restore data from backup
After reinstall of Mac OS X, you should restore data from backup, which should be valid and updated. If you face any concerns related to backup, you should use an effective Mac Recovery Software tool to recover data. Data Recovery Mac applications perform comprehensive data recovery using powerful scanning algorithms, which safely restore all the lost data from a logically affected Mac drive.
Stellar Phoenix Macintosh Data Recovery is a comprehensive product to provide systematic data recovery for Mac OS X 10.6 Snow Leopard, 10.5 Leopard, 10.4 Tiger and 10.3.9 Panther. It is a safe Mac File Recovery utility with impressive interface embedded with advanced options. The tool is compatible with HFS, HFSX, HFS+, HFS Wrapper and FAT file system drives.