If you’ve ever tested bad software, downloaded a file you shouldn’t have, mucked about in the Terminal with unpleasant results, or if you manage a bunch of Macs whose users do all that and more, you’ve probably wished you had a magic Undo command that could reverse the damage and restore your hard drive to a pristine state. That’s exactly what Deep Freeze Mac does.
Deep Freeze starts by taking a snapshot of your system in its clean state. After that, you can install software, create and save files, change settings, bookmark Web sites, and do pretty much anything you normally do. When you restart the Mac, Deep Freeze will discard all those changes and return the system to its original, clean condition. The effect is similar to Microsoft Virtual PC ’s ( ) Undo Drives mode, but for your entire Mac.
When Deep Freeze is installed on a Mac, an icon in the menu bar and above the Hard Drive icon tells you whether the drive is “frozen” or “thawed.” (“Frozen” means the configuration will return to its pristine state the next time it boots; “thawed” means that any changes users make will stick around, even after a reboot.) If you need to change a configuration or install software on the Mac, you can use the Menu Bar icon to switch between frozen and thawed. You can’t thaw a drive without supplying a password; you can also hide the Deep Freeze icons if you wish. If you need to keep files you’ve downloaded, you can save them to a thawed drive partition, or to a CD, DVD, external hard drive, or a USB flash memory drive. Unfortunately, you can’t freeze a FireWire or USB hard drive.
For network managers, Deep Freeze uses the file formats of Apple Remote Desktop. The Deep Freeze Assistant will install nine tasks in Apple Remote Desktop, which you can use to install Deep Freeze on groups of Macs as well as to freeze and thaw Macs over a network. The Deep Freeze Assistant can also create customized Deep Freeze installation packages complete with passwords.
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Deep Freeze Mac 2.03 is a straightforward, easy-to-use utility that does what it claims to do: automatically reset a Mac to pristine condition after a restart. It can save system administrators hours of cleaning up and troubleshooting public Macs, but it’s also a great way for individual users to safely try out new software or download files without worrying about how to undo the damage if things go wrong.
[ John Rizzo is the author of Mac Mini Hacks and Mods for Dummies (John C. Wiley, 2006) and is the publisher of MacWindows.com.]When you enable Deep Freeze, OS X will boot into a clean, “frozen” configuration—free of any changes users may have inadvertently made to the system.