Learn How to Use the Windows Registry Editor (Regedit) in One Easy Lesson
A previous article
discussed some basic facts about the Registry. In this tutorial, I’ll
explain how the Registry Editor works and show how to tweak the
Registry. Applies to Windows XP / Vista / 7.
Introduction
Many people like to configure Windows their own way and Windows is a
system with numerous possible tweaks. Most of these tweaks are actually
edits of the Registry. There are several ways to apply Registry changes
but the true tweaker often likes to go to the source and tune up the
Registry directly with the Windows Registry editor
Regedit.
Regedit is one of those Windows programs that Microsoft doesn't say much about. It isn’t listed in the
All Programs
menu and the Help function doesn’t say how to use it. In fact, in
Windows XP it warns, “Although you can use Registry Editor to inspect
and modify the registry, doing so is not recommended, as making
incorrect changes can damage your system.” Pretty offputting but the
caution is overdone. In Windows Vista/7, Microsoft relaxed a bit and
included a few more details in Help but still not enough to let anyone
understand how to use Regedit. If you are bold enough to go to Regedit
itself, you will find it has its own Help menu with some instructions
but they are rather sparse.
This tutorial will flesh out what Microsoft has omitted and give you all the information you need to begin editing the Registry.
But first, I must make the rules of Registry editing clear.
Rules for editing the Registry safely
I have edited the Registry hundreds of times over the years and have
developed the steps below for safe editing. I have messed things up once
or twice but I have always been able to get back to the original system
state without trouble because I followed the rules. Here are my five
rules for safer Registry editing:
-
The ironclad rule of Registry editing is that you must first back up
the Registry. For many, making a System Restore point is the most
convenient backup method. I also use the export facility of Regedit to make a copy of the Registry key that I am working on. Keep in mind that Regedit has no Undo function.
-
Know how to restore a Registry backup. It can be as simple as running System Restore or merging a backup REG file.
-
Make only one Registry edit at a time. Wait to see if everything works
the way you want before making any more changes to the Registry. Don't
forget that many Registry edits require that you log off or reboot
before they take effect.
-
Only use Registry edits recommended by known reliable sources. Many of
the common recommendations on the Internet are useless or nearly so.
And some are even harmful.
-
Remember Rule #1.
With the precautions out of the way, we can get down to learning about Regedit.
How to open Regedit
A quick way to access Regedit that applies to Windows XP, Vista, and 7 is the following:
-
Open the Run box with the keyboard combination Windows key + r
-
In the Run line, enter “regedit” (without quotes)
-
Click “OK”
-
Say “Yes” to User Account Control (Windows Vista/7)
The structure of the Registry as presented in Regedit
Using Regedit requires some knowledge of the basic structure of the
Registry. I would go further and say I think it is worthwhile to take a
look at the structure of the Registry even if you never intend to change
a single comma in it. Total ignorance about what is actually in the
Registry allows the imagination to assign mysterious and fearsome
properties to something that is actually just a database. You may not
remember any details but having once seen what is actually in the
Registry, you will be psychologically better prepared to do the type of
Registry operations that everybody should know- backing up and
restoring.
Types of Information in the Registry
The information that the computer system needs to have is divided
into two main categories. One is general information about the computer
itself. These are settings that apply system wide and include the
hardware on the system. This is named the
Local Machine. The other general category consists of settings that are specific to each user account and is labeled
Users. The particular user who is logged on is called the
Current User.
The Hierarchical Tree Structure
Information in the Registry is presented in a tree-like system akin
to folders and files. In the Registry, the containers for information
are called "keys". These are analogous to folders. Keys can have subkeys
just as folders can have subfolders. The name of data that is contained
in a key is called a "value". This is something analogous to a file
name. The actual data can have several formats and may be a string, a
number, or a series of numbers.
Just as the computer file and folder system has a root (usually a
hard drive) the Registry has root keys at the top of the hierarchy of
keys and values. I have mentioned the two general categories of
information and these constitute two root keys. Unfortunately, we now
have to deal with some Microsoft jargon. Table I shows the names that
Microsoft uses. The names of root keys have "HKEY" tacked on the front.
and these keys are often called "hives". Although five root keys are
used, three of them are really just subkeys or combinations of subkeys
of the two main keys, HKLM and HKU. The additional root keys make
programming easier.The abbreviations that are given are often used in
writing scripts and
INF files.
Table I. Root keys or Hives
|
Keys |
Abbreviation |
Description |
|---|
|
HKEY_CLASSES_ROOT |
HKCR |
Stores file association and COM object registration |
|
HKEY_CURRENT_USER |
HKCU |
Stores data associated with the account currently logged on |
|
HKEY_LOCAL_MACHINE |
HKLM |
Stores system-related information |
|
HKEY_USERS |
HKU |
Stores information about all the accounts on the machine |
|
HKEY_CURRENT_CONFIG |
HKCC |
Stores information about the current machine profile |
Using Regedit
Regedit is a two-pane interface with keys in the left pane (key pane)
and value names with the corresponding data in the right pane (value
pane). The setup is not unlike Windows Explorer with keys analogous to
folders and values analogous to files. An example is shown in the figure
below. This is from Windows XP but Vista/7 is very similar.
Figure 1. Registry Editor (Regedit)
 |
The bottom of the window for Regedit shows the path of the currently
highlighted key as can be seen in the figure above. This is an example
of typical Registry address although the leading "My Computer" is
normally omitted.
Also listed in the right or value pane is the type of data contained
in a value. There are a number of formats that data can take and the
usual ones that most PC users will encounter are given in Table II. I
have omitted the more esoteric types. The three listed in the table
constitute the vast majority of all Registry entries. Other data types
are described at
this Microsoft link.
Table II. Common Registry data types
|
Data type |
Description |
|---|
|
REG_BINARY |
Binary data . Usually in hexadecimal notation. An example is 0xA8 |
|
REG_DWORD |
Double word (32 bits). Can be edited in either hexadecimal or decimal |
|
REG_SZ |
A string. Figure 1 shows examples in the right pane. |
Menus in Registry Editor
Regedit has some of the same menus that are so familiar throughout
Windows. The menu bar can be seen near the top of Figure 1. Shown below
are two commonly used menus.
|
Figure 2. File menu |
Figure 3. Edit menu |
|---|
 |
 |
The File menu has the functions "Import" and "Export" that can be
used to backup and restore individual Registry keys with REG files. The
next section will have more detail about this important function.
As you would expect, the "Edit" menu is where commands are located
for making changes to the Registry. Keys and values can be deleted,
added, or renamed. (Permission settings on keys can also be edited but
that is an advanced subject beyond our scope.) Another two very useful
functions are "Find..." and "Find Next". The Registry has thousands of
keys and these search functions are very necessary. Unfortunately, the
search function cannot find binary values or REG_DWORD entries. It
searches key names, value names, and string data.
The Edit menu also contains a useful entry "Copy Key Name" that sends
the path of the key to the clipboard, Since path names can be quite
long, this can be very useful.
Another
menu that can be quite useful is "Favorites". If you find that there
are is a certain key that you modify often, this key can be added to the
"Favorites' list for easy access. The example of a "Favorites" menu
shown on the right contains three favorites. Note the names have been
chosen by this user and can be anything that is a convenient reminder.
They actually refer to specific Registry keys, which can have very long
path names.
Here is how to back up a key (remember, a key is something like a folder):
-
Open Regedit and highlight the key
-
Open the "file" menu and click "Export". An alternative method is to right-click the key and choose "Export"
-
A standard dialog box for saving files will open. For most cases, you
will choose to save as a registration or REG file. This is a text file
with extension .reg that is a copy of the highlighted Registry key
-
Save it someplace safe
Note that whole keys and not single values are involved. To restore a
Registry key, you can use the "Import" function. However, it is easier
to merge REG files into a Registry by right-clicking the file and
choosing "Merge". On many machines the default
left double-click
on a REG file will also create a merge. I prefer to change the
double-click action to "Edit" so that accidental mergers do not happen.
Notice that I use the word "merge". REG files do not replace keys but
add to them, something to keep in mind. Anything extra that you may have
added is not deleted. Some experienced PC users prefer to do any actual
editing in the exported REG file and then to merge the edited file.
This prevents accidentally doing something to the wrong key.
Keep in mind that Regedit has no "undo" function. What's done is done.
Editing the Registry
There are many useful adjustments to the Windows configuration or
behavior that can be made by simple editing of the Registry. Unless you
are a trained IT professional, you should probably limit Registry
editing to one or two values at a time. I will limit this discussion to
this type of straightforward scenario.
For
the most part, direct Registry editing means changing a
value. Highlight the value in question in the right-pane of Regedit.
Then choose "Modify" from the "Edit" menu or right-click the value and
choose "Modify" from the context menu. For strings, a box like the one
shown in the nearby picture will open. As a specific example, consider
the last value in the right-pane of Figure 1. The time that the system
waits for a service to close at Shutdown is controlled by the entry for
the value,
WaitToKillServiceTimeout.
The value is in milliseconds and the default is 20000 (20 seconds). To
make things close up more quickly, you could change the value to 10000
(10 seconds). Or you might need to make it longer for certain systems.
Enter the desired string in the line "Value data" and click OK.
A
great many Registry values are strings but another type of data that is
common is the "DWORD". A slightly different box will appear if you are
editing a REG_DWORD value. The figure on the left shows the appropriate
box. Note that when entering a DWORD value, you need to specify the base
for the number. Be careful to be sure that you have chosen correctly
between hexadecimal and decimal. You can enter either but the number
that you enter must correspond to the correct value for the chosen base.
In the example here the decimal number "96" would have to be "60" if
hexadecimal were picked for the base.
And so we come to the end of the unveiling of the mysteries of the Registry. Go forth and edit well but carefully—
Vic Laurie
