In the Windows registry, what does HKCU stand for?

In the Windows registry, what does HKCU stand for?

• HKEY_COMMON_USER
• HKEY_COMMAND_USER
• HKEY_COMPUTER_USER
• HKEY_CURRENT_USER 

EXPLANATION

How to Get to HKEY_CURRENT_USER

HKEY_CURRENT_USER is a registry hive, one of the easier types of things to find in Registry Editor:

1. Open Registry Editor.
2. Locate HKEY_CURRENT_USER in Registry Editor, from the pane on the left.
3. Double-tap or double-click on HKEY_CURRENT_USER, or single click/tap the small arrow or plus icon on the left, if you want to expand it.
   

Newer versions of Windows use an arrow as that button to expand registry hives but others have a plus sign.

Don't See HKEY_CURRENT_USER?

HKEY_CURRENT_USER may be hard to find if Registry Editor has been used on your computer before, since the program takes you directly to the last place you were. Since all computers with Windows Registry have this hive, you aren't actually missing HKEY_CURRENT_USER if you can't see it, but you might need to hide a few things in order to find it.

Here's what to do: From the left-hand side of Registry Editor, scroll to the very top until you see Computer and HKEY_CLASSES_ROOT. Select the arrow or plus sign to the left of the HKEY_CLASSES_ROOT folder to minimize/collapse that entire hive. The one just below it is HKEY_CURRENT_USER.

Registry Subkeys in HKEY_CURRENT_USER

Here are some common registry keys you might find under the HKEY_CURRENT_USER hive:

• HKEY_CURRENT_USER\AppEvents
• HKEY_CURRENT_USER\Console
• HKEY_CURRENT_USER\Control Panel
• HKEY_CURRENT_USER\Environment
• HKEY_CURRENT_USER\EUDC
• HKEY_CURRENT_USER\Identities
• HKEY_CURRENT_USER\Keyboard Layout
• HKEY_CURRENT_USER\Network
• HKEY_CURRENT_USER\Printers
• HKEY_CURRENT_USER\Software
• HKEY_CURRENT_USER\System
• HKEY_CURRENT_USER\Volatile Environment

The registry keys located under the HKEY_CURRENT_USER hive on your computer may differ from the list above. The version of Windows you're running, and the software you have installed, both determine what keys may be present.

Since the HKEY_CURRENT_USER hive is user specific, the keys and values contained in it will differ from user to user even on the same computer. This is unlike most other registry hives which are global, like HKEY_CLASSES_ROOT, which retain the same information across all users in Windows.

HKCU Examples

Following is some information on just a few sample keys found under the HKEY_CURRENT_USER hive:

HKEY_CURRENT_USER\AppEvents\EventLabels

This is where labels, sounds, and descriptions are found for various functions in Windows and third-party apps, like fax beeps, completed iTunes tasks, low battery alarm, mail beeps, and more.

HKEY_CURRENT_USER\Control Panel

Under \Control Panel\Keyboard is where a few keyboard settings are found, like the keyboard delay and keyboard speed options, both of which are controlled via the Repeat delay and Repeat rate settings in the Keyboard Control Panel applet.

The Mouse applet is another one whose settings are stored in the HKEY_CURRENT_USER\Control Panel\Mouse key. Some options there include DoubleClickHeight, ExtendedSounds, MouseSensitivity, MouseSpeed, MouseTrails, and SwapMouseButtons.

Yet another Control Panel section is dedicated solely to the mouse cursor, found under Cursors. Stored here is the name and physical file location of default and custom cursors. Windows uses still and animated cursor files that have the CUR and ANI file extensions, respectively, so most of the cursor files found here point to files of those types in the %SystemRoot%\cursors\ folder.

The same is true for the HKCU Control Panel Desktop key that defines lots of Desktop-related settings in values like WallpaperStyle that describes whether to center the wallpaper or stretch it across the display. Others in this same location include CursorBlinkRate, ScreenSaveActive, ScreenSaveTimeOut, and MenuShowDelay.

HKEY_CURRENT_USER\Environment

The Environment key is where environment variables like PATH and TEMP are found. Changes can be made here or through Windows Explorer, and they'll be reflected in both places.

HKEY_CURRENT_USER\Software

Lots of user-specific software entries are listed in this registry key. One example is the location of the Firefox web browser program. This subkey is where the PathToExe value is found that explains where firefox.exe is located within the installation folder:

HKEY_CURRENT_USER\Software\Mozilla\Mozilla Firefox\57.0 (x64 en-US)\Main

More on HKEY_CURRENT_USER

The HKEY_CURRENT_USER hive is actually just a pointer to the key located under the HKEY_USERS hive that's named the same as your security identifier. You can make changes in either location since they are one and the same.

The reason HKEY_CURRENT_USER even exists, given that it's just a reference point to another hive, is that it provides an easier way to view the information. The alternative is to find the security identifier of your account and navigate to that area of HKEY_USERS.

Again, everything seen in HKEY_CURRENT_USER pertains only to the user that's currently logged on, not any of the other users that exist on the computer. This means that each user that logs in will pull their own information from the corresponding HKEY_USERS hive, which in turn means HKEY_CURRENT_USER will be different for each user that views it.

Because of how this is set up, you could actually just navigate to a different user's security identifier in HKEY_USERS to see everything they would see in HKEY_CURRENT_USER when they're logged in.