Pane Relief: Registry Management Tools

• By Rick Cook
• Feb 10, 2006

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Special Edition Using Microsoft Windows XP Professional, 3rd Edition

There are two problems with the Windows registry: First, it’s a pretty dangerous place; second, it’s a time-consuming one. Windows administrators who have to do things in the registry—in other words, most administrators—need all the help they can get. Fortunately, a number of tools are available to help you manage your system’s registry.

Registry management tools range from those that come with Windows, to freeware and shareware, to full commercial products. Some of them do very limited, specific jobs. Others are more general.

Working with the Registry

The thing that makes the registry so important is also what makes it so dangerous. The registry is the central repository for all the settings used by the operating system. It’s basically a much-expanded, much-more-complex successor to the WIN.INI file in the early versions of Windows.

Physically, the Windows registry consists of several files with thousands of lines of computer gibberish. It’s not easy to read or understand, and almost nobody really comprehends the whole thing. The registry is not user-friendly. Or administrator-friendly, come to that. The underlying assumption is that the registry will be read and written by the operating system and applications, not by users or the administrator.

Structure of the Registry

With its usual love of confusing neologism, Windows calls the major sections of the registry hives. Hives consist of nodes and each node contains a registry entry called a key. Keys can have multiple sub-keys, and each terminal key or sub-key (the leaves on the registry tree) has a value. The value can be a number, a Boolean, one of several different kinds of text strings, or other things, depending on what’s appropriate. Think of it as a grove of trees with each hive as a trunk and the values of the keys as the leaves.

A simple registry key looks like this:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NfsSvr\Parameters

Value name: UseWriteCache

Value type: REG_DWORD

If I’ve managed to type all that correctly, this simple key controls caching in NFS for some versions of Windows. This one is simple because it’s more or less in English. Some of keys are named by strings of computer-generated letters and numbers.

The first line of the key is the path through the registry to this particular key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NfsSvr\Parameters

The next line is the key’s name:

Value name: UseWriteCache

The third line tells you what kind of value the key requires:

Value type: REG_DWORD

There should also be a line for the actual value.

Registry Cholesterol

Incomprehensibility of registry keys aside, there’s a lack of error checking, or even redundancy. (Note: Redundancy is a good thing in preventing errors.) Every single character, underscore, and space in every registry key has meaning. With few exceptions, the registry will cheerfully accept any changes you choose to make, no matter how nonsensical or misguided. Something as simple as a typo can turn even the most powerful computer into a desk ornament.

As a result, the registry has a well-deserved reputation as something that is best left completely alone.

Except, of course, that you can’t just leave it alone. By its nature, the registry accumulates junk. When applications are installed, they usually add or modify registry keys. Nice applications play well with others and change the registry back when they’re uninstalled. A lot of applications aren’t very good about that, though, and some are real brats. Obviously, adware and spyware are the juvenile delinquents of the registry. They not only don’t change things back, many of them make it as hard as possible to change things by other means.

The symptoms of this buildup of registry cholesterol is hardening of the computer’s arteries. The system slows and may exhibit odd behavior, such as refusing to print from Adobe Acrobat. (I’ve had this experience.) If the buildup is really bad, you can have a "computer coronary," where the system simply crashes. By the time this happens, though, you may have literally thousands of useless or problem keys in the registry that need fixing.

Then too, sometimes you have to modify registry settings. In fact, sometimes you will need to modify a dozen or more registry keys in a single sitting. This is extremely difficult to do without making a mistake.

Rules for the Registry

There are two major rules for working on the registry

• Always back up the registry before doing anything! If you don’t have a backup of the registry, taken immediately before you started fooling with it, sooner or later you’re going to find yourself screwed. It’s that simple.
• In Windows XP, set a restore point before working on the registry. Rolling back to a restore point in XP is a fast way to unscrew registry screwups, but it won’t work if you’ve munged the registry so badly that your system won’t start.

A third rule is for system administrators: Keep users out of the registry! This means changing permissions in Windows Server 2003 because by default users can change the keys related to their accounts. While users can’t mess with the rest of the registry, you don’t want them trying to modify their own keys either.

You can lock users out of the registry either by setting permissions in the Registry Editor (discussed next) or by removing the Registry Editor from users’ computers.