Skip to content
Thoughtful, detailed coverage of everything Apple for 34 years
and the TidBITS Content Network for Apple professionals

The Public Mac – MacPrefect and DiskPrefect

Have you ever maintained a Macintosh shared by multiple users? Or shared your own Mac with coworkers or family members? If so, you may have faced the nightmare of randomly trashed applications, misplaced documents, and changed settings. If you shop around, you’ll find many utilities that decrease the chaos involved in sharing a Mac, and this article discusses one possible solution – a program from Hi Resolution, called MacPrefect, and its companion program, DiskPrefect. MacPrefect enables you to prevent other "experts" from interfering with the Macintosh environment that you so carefully set up.

Locking Out the Unwashed Masses — You may like the people who use your Mac, but that doesn’t mean you want them poking around in places where they don’t belong. As an extreme measure, you can lock the hard disk, so that others cannot move, rename, or save files on the hard disk. If you don’t want to lock the entire disk, you can lock individual folders (locking a folder locks all the folders inside it). If a user tries to save to a locked folder, he gets a message informing him that he can’t save to the locked location. You can customize the message so it directs the user to an appropriate location.

Fortunately, programs can get into the System Folder, even if users can’t. According to the MacPrefect folks, "MacPrefect allows applications to create and maintain their own preference files or temporary files as required. This ensures that locking the System folder in its entirety is possible with no resulting interference to the normal action of applications."

If you choose to allow users to save on the hard disk, you can "sweep" the disk clean of files at startup. Any files older than a certain number of days can be removed – either all such files, or until a specified amount of disk space frees up. This feature would be especially useful for a public Macintosh where you don’t want users’ files cluttering the hard disk.

If you do maintain a public Macintosh, you may be particularly concerned about piracy – you don’t want pirated software on the public Mac, and you don’t want users making unauthorized copies of programs from the Mac. A feature called Copy Control meets these concerns by preventing users from copying certain file types to or from the hard disk.

As an additional anti-piracy measure (or as an additional control mechanism) launch keys enable you to you control which programs can run on the Mac. An application can be prevented from running unless it has a launch key file in its folder. The launch key feature doesn’t care what disk the program is on, so it prevents users from launching software stored on floppy disks (though you can set it to allow launches from CD-ROMs). You can also configure MacPrefect to only allow software to launch if the software is stored on the startup volume.

MacPrefect has a number of other features that prevent users from completing all manner of actions, such as filling up the hard disk by repeatedly taking screen shots, changing control panel settings, and changing the name of the hard disk.

Bypassing the Security System — "This all sounds wonderful," you may be thinking, "but I bet any savvy user can weasel around MacPrefect by booting with the Shift key down or booting from a floppy disk." Hi Resolution thought of that and added additional security features. MacPrefect allows you to disable the Shift key’s startup function, and DiskPrefect takes security a step further by preventing users from booting from floppy disks. DiskPrefect comes as a separate, companion product to MacPrefect, although you get both together if you purchase the software in the U.K. or Australia.

To disable DiskPrefect, you must use a copy of MacPrefect with the correct serial number. This means your machine is safe even if a user obtains another copy of MacPrefect. DiskPrefect only works with Apple formatted disks, but won’t damage other hard disks if you attempt to install it on them.

DiskPrefect comes with a Lockpick application, which you can use to unlock the disk in an emergency. To use Lockpick, you must have a random authorization code, and you must get the code from Hi Resolution each time you need to use Lockpick.

Conclusion — I found MacPrefect to be reliable in operation and straightforward to use. With the addition of DiskPrefect, your beloved Mac can be protected against assault by all but the most expert of hackers.

Pricing varies for corporate and educational customers, depending on the number of copies purchased.

Hi Resolution, Inc. (U.S.) — <[email protected]>
Hi Resolution, Ltd. (U.K.) — <[email protected]>

Subscribe today so you don’t miss any TidBITS articles!

Every week you’ll get tech tips, in-depth reviews, and insightful news analysis for discerning Apple users. For over 33 years, we’ve published professional, member-supported tech journalism that makes you smarter.

Registration confirmation will be emailed to you.

This site is protected by reCAPTCHA. The Google Privacy Policy and Terms of Service apply.