Overview of the Windows 2000 Registry Editors

Microsoft^® Windows 2000 Knowledge Center

The Windows 2000 Registry Editors

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Overview of the Registry Editor (Regedit32)

The Registry Editor is an advanced tool that you can use for changing settings in your system registry, which contains information about how your computer runs. Windows 2000 stores its configuration information in a database (the registry) that is organized in a tree format. Although the Registry Editor will enable you to perform such tasks as inspect and modify the Windows registry, in most cases you do not need to do so unless you are repairing a specific problem that cannot be resolved in another way, or you are doing other specific tasks such as apply user-specific security changes. Although you do not need to be an advanced user to edit the Windows Registry, you should be thoroughly familiar with the methods necessary to backup and restore the registry. This familiarity will allow you to safely use Registry Editor for such tasks as eliminating duplicate entries or deleting entries for programs that have been uninstalled or deleted.

Folders represent keys in the registry and are shown in the navigation (Left) pane. In the topic (Right) pane, the value entries in a key are displayed. When you double-click a value entry, it opens an editing dialog box.

Again, you should edit your registry entries only if it is absolutely necessary. If there is an error in your registry and your computer ceases to function properly, you can restore the registry to its last known good state (that state it was in before the changes) when you last successfully started your computer.

Registry Editor Keys

The Registry Editor displays windows, each of which represents a predefined key on the local computer.

Note: When accessing the registry of a remote computer, only two predefined keys, HKEY_USERS and HKEY_LOCAL_MACHINE, appear.

Window/predefined key	Description
HKEY_CURRENT_USER	Contains the root of the configuration information for the user who is currently logged on. The user’s folders, screen colors, and Control Panel settings are stored here. This information is referred to as a user’s profile.
HKEY_USERS	Contains the root of all user profiles on the computer. HKEY_CURRENT_USER is a subkey of HKEY_USERS.
HKEY_LOCAL_MACHINE	Contains configuration information particular to the computer (for any user).
HKEY_CLASSES_ROOT	Is a subkey of HKEY_LOCAL_MACHINE \Software. The information stored here ensures that the correct program opens when you open a file by using Windows Explorer.
HKEY_CURRENT_CONFIG	Contains information about the hardware profile used by the local computer at system startup.

Within Registry Editor, you can assign value entries to new keys or you can alter the value entries assigned to a currently selected key. Value entries appear in the registry as strings that consist of three components separated by colons. For example,

RefCount : REG_DWORD : 0x1

corresponds to the values:

Entry name	RefCount
Entry type	REG_DWORD
Entry value	0x1

Managing The Registry

To open the registry of the local computer

• On the Registry menu, click Open Local.

To open the registry of a remote computer

1. On the Registry menu, click Select Computer.
2. In Computer, type, or in Select Computer, click, the name of the computer whose registry you want to open, and then click OK.

Note:

• You can open two predefined keys (HKEY_USERS and HKEY_LOCAL_MACHINE) of a remote computer registry.

Viewing Data in Read Only mode

• On the Options menu, click Read Only Mode.

  Note: Read Only Mode protects your registry data from potentially damaging, accidental changes. When you click Read Only Mode, Registry Editor does not save any changes that you make.

Confirming the Deletion of a registry entry

• On the Options menu, click Confirm on Delete.

  Note: If you are not using Read Only mode, you should use Confirm on Delete to protect your registry data from accidental deletions. When Confirm on Delete is selected, Registry Editor presents a dialog box asking for confirmation any time that you delete a registry key or a value entry.

Updating registry information

Registry Editor provides the following ways to update registry information:

• Auto Refresh (on the Options menu) automatically updates the registry when any change is made to registry data.
• Refresh All (on the View menu) updates all of the information in all Registry Editor windows.
• Refresh Active (on the View menu) updates only the information in the active Registry Editor window.

Note:

• When Auto Refresh is in effect, a check mark appears next to the command and both Refresh All and Refresh Active on the View menu are unavailable.
• You cannot use Auto Refresh while displaying a remote registry. If you click Auto Refresh while displaying a remote registry, the manual refresh options (Refresh All and Refresh Active) are not available. Although Auto Refresh appears to be working as it would if a local registry window were displayed, the contents of the remote window will not be automatically refreshed.

To save a registry subtree as a text file

1. Select the key that you want to save as a text file.
2. On the Registry menu, click Save Subtree As.
3. In Save in, enter the file location.
4. In File name, enter the file name.
5. In Save as type, make sure it says Text Files.
6. Click Save.

Note:

• Saving the contents of a registry key as a text file includes all of the key’s descendent keys and all of the value entries assigned to its descendent keys. These are saved to the local or network location that you specify.

To restore the registry

1. Because you will have to restart your computer, print this topic first. In this window, click Options and then click Print.
2. On the taskbar, click Start, and then click Shut Down.
3. Click Restart, and then click OK.
4. When you see the message Select an operating system, press F8.
5. Use the arrow keys to highlight Last Known Good Configuration, and then press ENTER.
6. Follow the instructions on the screen.

Note

• Following this procedure will restore your registry to its state when you last successfully started your computer.

Editing Registry Information

Searching for a key in Registry Editor

1. On the View menu, click Find Key.
2. In Find what, type the name of the key you want to find.
3. You can narrow your search by doing the following:
   • To find only occurrences of a word that are not part of a larger word, select the Match whole word only check box.
   • To identify only those keys in the registry with the combination of uppercase and lowercase letters specified in Find what, select the Match case check box.
4. In Direction, click the direction you want the search to proceed through the registry:
   • To search the portion of the registry tree above the insertion point or selection, click Up.
   • To search the portion of the registry tree below the insertion point or selection, click Down.
5. Click Find Next to find each subsequent occurrence of the specified text until all occurrences have been found.

 Using the String Editor

1. Select a value entry of the type REG_SZ or REG_EXPAND_SZ.
2. On the Edit menu, click String.
3. In String, enter any changes, and then click OK.

   Note: A string is a sequence of characters. Many value entries in the registry are written in a string (REG_SZ) or in an expandable string (REG_EXPAND_SZ) format. An expandable string usually consists of text, but also contains a variable that will be replaced when it is called by an application. For example, in the value entry %systemroot%\System32\Bootok.exe, %systemroot% is the expandable portion of the variable, and will be replaced by the actual location of the directory that contains the Windows 2000 system files. If a value entry in Registry Editor has a REG_SZ or a REG_EXPAND_SZ prefix, you can edit the value entry using the String Editor.

Using the Binary Editor

1. Click the value entry that you want to edit.
2. On the Edit menu, click Binary.
3. Under Data Format, click one of the following:
   • To represent your data as a sequence of binary digits, click Binary.
   • To represent your data as a sequence of hexadecimal digits, click Hex.
4. In Data, enter any changes, and then click OK.

   Note: Many value entries in the registry are written as raw binary data. If a value entry is preceded by the prefix REG_BINARY, the value entry is written as binary data, and you must use the Binary Editor to edit this value entry. You can also use the Binary Editor to edit any other value entry, regardless of the format in which the entry is written.

Using the DWORD Editor

1. Click a value entry of the type REG_DWORD.
2. On the Edit menu, click DWORD.
3. In Data, enter any changes.
4. Under Radix, click one of the display options.
   • To display the data as a binary (base-2) number, click Binary.
   • To display the data as a decimal (base-10) number, click Decimal.
   • To display the data as a hexadecimal (base-16) number, click Hex.

   Note: DWORD refers to data that is represented by a number that is four bytes long. If a value entry contains the prefix REG_DWORD, the entry is written in the DWORD format.

Using the Multi String Editor

1. Click a value entry of the type REG_MULTI_SZ.
2. On the Edit menu, click Multi String.
3. In Data, enter any changes, and then click OK.

   Note: If a value entry contains the prefix REG_MULTI_SZ, the value entry is written as a multiple string.

Registry Security

You can assign permissions to a registry key

1. Click the key to which you want to assign permissions.
2. On the Security menu, click Permissions.
3. Assign an access level to the selected key as follows:
   • To grant the user permission to read the key contents but not to save any changes made to the file, select the Allow check box for Read.
   • To grant the user permission to open, edit, and take ownership of the selected key, select the Allow check box for Full Control.
   • To grant the user special permission in the selected key, click Advanced.
4. If you are assigning permissions to a subkey and you want the inheritable permissions assigned to the parent key to apply to the subkey also, select the Allow inheritable permissions from parent to propagate to this object check box.

   Note: If you own a registry key, you can specify the users and groups that can open that key. To determine who can open your registry keys, you need to assign permissions to them. You can add or remove users or groups from the list of those authorized to access your registry keys at any time

Assigning Special Access to a registry key

1. Click the key to which you want to assign Special Access.
2. On the Security menu, click Permissions.
3. Click Advanced, and then double-click the user or group to whom you want to assign Special Access.
4. Under Permissions, select the Allow or Deny check box for each permission you want to allow or deny.

   Note: Assigning Special Access is useful for situations in which you need to assign permissions that are not defined by either Read or Full Control.

   If you are assigning permissions to a subkey and you want the inheritable permissions assigned to the parent key to apply to the subkey also, select the Allow inheritable permissions from parent to propagate to this object check box.

   If you are assigning permissions to a parent key and want any existing permissions of its subkeys replaced with the parent key’s inheritable permissions, select the Reset permissions on all child objects and enable propagation of inheritable permissions check box.

Adding users or groups to the Permissions List

1. Click the key whose Permissions list you want to change.
2. On the Security menu, click Permissions, and then click Add.
3. In the Select Users, Computers, or Groups dialog box, in Look in, click the computer or domain of the users and groups you want to view.
4. Click the name of the user or group, click Add, and then click OK.
5. In the Permissions dialog box, under Permissions, assign a type of access to the selected user or group as follows:
   • To grant the user permission to read the key contents but not to save any changes made to it, select the Allow check box for Read.
   • To grant the user permission to open, edit, and take ownership of the selected key, select the Allow check box for Full Control.

   Note: If the check boxes under Permissions are shaded, the key has inherited permissions from the parent key.

   To allow permissions assigned to a parent key to apply to its subkeys also, select the Allow inheritable permissions from parent to propagate to this object check box. This check box appears only if you are setting permissions on a subkey.

   In the Select Users, Computers, or Groups dialog box, if you type the name, rather than selecting it, click Check Names before clicking OK.

Granting Full Control of a registry key

1. Click the key to which you want to grant Full Control.
2. On the Security menu, click Permissions.
3. Under Name, click the user to whom you want to grant Full Control of your registry key.
4. Under Permissions, select the Allow check box for Full Control.

   Note:You can permit another user to take ownership of a registry key only if you are the current owner of the key. To permit a user to to take ownership of a registry key, you must first grant the user Full Control of the key.

Auditing Activity on a registry key

1. Click the key you want to audit.
2. On the Security menu, click Permissions.
3. Click Advanced, and then click the Auditing tab.
4. Double-click the name of a group or user.
5. Under Access, select or clear the Successful and Failed check boxes for the activities that you want to audit or to stop auditing:
   

   Select	To audit
   Query Value	Any attempts to read a value entry from a registry key
   Set Value	Any attempts to set value entries in a registry key
   Create Subkey	Any attempts to create subkeys on a selected registry key
   Enumerate Subkeys	Any attempts to identify the subkeys of a registry key
   Notify	Any notification events from a key in the registry
   Create Link	Any attempts to create a symbolic link in a particular key
   Delete	Any attempts to delete a registry object
   Write DAC	Any attempts to write a discretionary access control list on the key
   Write Owner	Any attempts to change the owner of the selected key
   Read Control	Any attempts to open the discretionary access control list on a key

   Note: You must be logged on as an administrator or a member of the Administrators group to complete this procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure. You must first add users and groups before specifying the events to audit.

Adding Users or Groups to the Audit list

1. Click the key you want to audit.
2. On the Security menu, click Permissions.
3. Click Advanced, click the Auditing tab, and then click Add.
4. In Look in, click the computer or domain of the users and groups you want to view.
5. Click the name of the user or group you want to add, and then click OK to open the Auditing Entry dialog box.

   Note: You must be logged on as an administrator or a member of the Administrators group to complete this procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure. You must first add a user or group before specifying which events to audit.

Taking Ownership of a registry key

1. Click the key you want to take ownership of.
2. On the Security menu, click Permissions.
3. Click Advanced, and then click the Owner tab.
4. Under Change owner to, click the new owner, and then click OK.

   Note: You can take ownership of a registry key if you are logged on as an administrator or if you have been specifically assigned the permission to take ownership of the registry key by the current owner.

Changing the Appearance of the Registry Editor

To switch between the tree and data views

• On the View menu, click one of the following display options:
  • To view both the tree and the data, click Tree and Data.
  • To view only the registry tree, click Tree Only.
  • To view only the value entries of a registry tree, click Data Only.

    Note: Tree and Data is the default setting. You can use the Tree menu options to change the appearance of the registry tree.

Splitting the Registry Editor window

1. On the View menu, click Split.
2. Use the mouse or the arrow keys to move the vertical bar.
3. Click to set the dividing bar at its current location.

   Note: To cancel Split, press ESC before clicking.

Printing your Registry Information

To print a subtree

1. In the tree pane of a Registry Editor window, select a key.
2. On the Registry menu, click Print Subtree.

   Note: When you print a key, Registry Editor prints the key, its descendent keys, and all of the value entries of all of its descendent keys.

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