Windows Tutorials - Herong's Tutorial Examples - Version 5.60, by Dr. Herong Yang

Registry Hives - HKCR, HKCU, HKLM, HKU, HKCC, and HKPD

This section provides quick introductions on the Windows registry hives - top level registry keys on Windows XP systems.

Information stored in the Registry is divided into several predefined sections called "hives". A registry hive is a top level registry key predefined by the Windows system to store registry keys for specific objectives.

On my Windows XP system, the Registry has 6 registry hives:

  • HKCR - Abbreviated from the registry key name HKEY_CLASSES_ROOT. HKCR stores information about registered applications, such as Associations from File Extensions and OLE Object Class IDs tying them to the applications used to handle these items.
  • HKCU - Abbreviated from the registry key name HKEY_CURRENT_USER. HKCU stores settings that are specific to the currently logged-in user. The HKCU key is a link to the subkey of HKEY_USERS that corresponds to the user; the same information is reflected in both locations.
  • HKLM - Abbreviated from the registry key name HKEY_LOCAL_MACHINE. HKLM stores settings that are general to all users on the computer. On my XP system, HKLM contains five subkeys, HARDWARE, SAM, SECURITY, SOFTWARE and SYSTEM.
  • HKU - Abbreviated from the registry key name HKEY_USERS. HKU contains subkeys corresponding to the HKEY_CURRENT_USER keys for each user registered on the machine.
  • HKCC - Abbreviated from the registry key name HKEY_CURRENT_CONFIG. HKCC contains information gathered at runtime; information stored in this key is not permanently stored on the hard disk, but rather regenerated at boot time.
  • HKPD - Abbreviated from the registry key name HKEY_PERFORMANCE_DATA. HKPD provides runtime information into performance data provided by either the operating system kernel itself or other programs that provide performance data. This key is not displayed in the Registry Editor, but it is visible through the registry functions in the Windows API.

If you run "regedit.exe" on a Windows XP system, you should see 5 visible registry hives as shown in this picture:
Registry Hives - Top Keys

Table of Contents

 About This Windows Tutorial Book

 Introduction to Microsoft Windows

 Introduction to Windows Explorer

 Introduction to Internet Explorer

 "Paint" Program and Computer Graphics

 GIMP - GNU Image Manipulation Program

 JPEG Image File Format Quality and Size

 GIF Image File Format and Transparent Background

 "WinZip" - ZIP File Compression Tool

 "WinRAR" - RAR and ZIP File Compression Tool

 FTP Server, Client and Commands

 "FileZilla" - Free FTP Client and Server

 Web Server Log Files and Analysis Tool - "Analog"

 Spyware Adware Detection and Removal

 IE Addon Program Listing and Removal

 Vundo (VirtuMonde/VirtuMundo) - vtsts.dll Removal

 Trojan and Malware "Puper" Description and Removal

 VSToolbar (VSAdd-in.dll) - Description and Removal

 Spybot - Spyware Blocker, Detection and Removal

 Setting Up and Using Crossover Cable Network

 Home Network Gateway - DSL Modem/Wireless Router

 Windows Task Manager - The System Performance Tool

 "tasklist" Command Line Tool to List Process Information

 "msconfig" - System Configuration Tool

 Configuring and Managing System Services

Windows Registry Key and Value Management Tools

 What Is Windows Registry?

Registry Hives - HKCR, HKCU, HKLM, HKU, HKCC, and HKPD

 Registry Supporting Files - Registry Backups

 What Is the Registry Editor - "regedit.exe"

 "regedit.exe" - Finding Registry Keys for FreeCell

 "regedit.exe" - Viewing Registry Values

 "regedit.exe" - Changing Registry Values

 "regedit.exe" - Exporting Registry Keys

 "regedit.exe" - Importing Registry Keys

 Command Line Console Registry Tool - "reg.exe"

 "reg.exe" - Query Registry Keys and Values

 Startup Programs Removal for Better System Performance

 Winsock - Windows Sockets API

 Java on Windows

 Glossary of Terms

 Outdated Tutorials

 References

 PDF Printing Version

Registry Hives - HKCR, HKCU, HKLM, HKU, HKCC, and HKPD - Updated in 2014, by Dr. Herong Yang