Structure

SK/UK = System key/User key: This key can be used as a user key under HKEY_CURRENT_USER or as system key affecting all users on the machine under HKEY_CURRENT_USER. Unless otherwise stated all keys are DWORD, 0 disables the feature and 1 enables it.

HKEY_CLASSES_ROOT

Contains software settings about drag-and-drop operations, handles shortcut information, and other user interface information. There is a subkey here for every file association that has been defined.

  • AllFilesystemObjects\\shellex
    • ContextMenuHandlers
      • Copy To: Create this key to add a useful "Copy to.." entry for all files/folders, set the default value to {C2FBB630-2971-11d1-A18C-00C04FD75D13} .
      • Move To: As above except the default value must be {C2FBB631-2971-11d1-A18C-00C04FD75D13} .
    • CLSID
      • {87D62D94-71B3-4b9a-9489-5FE6850DC73E} This class ID relates to the data-extraction from AVIs for previewing data within them in an Explorer view. Sometimes Explorer goes mad and tries to extract the whole file in tiny segments and hangs Explorer until it is done. This can be avoided by prefixing the class ID with a dish and thus disabling the feature.
      • {20D04FE0-3AEA-1069-A2D8-08002B30309D} This class ID relates to the My Computer icon on the desktop.
        • LocalisedString: (string) The text that appears for the My Computer icon can be manipulated here. For instance Environment variables can be inserted to read: %username% on %computername%. If IE5.5 or earlier or pre XP alter the part of key that reads "My Computer" for instance it could read "\@C:\\WINNT\\system32\\shell32.dll,-9216\@1033,%USERNAME% on %COMPUTERNAME%". If IE6+ or XP then the key simply reads the actual name under the icon itself, for example: "%USERNAME% on %COMPUTERNAME%".

HKEY_CURRENT_USER

Contains settings regarding the currently logged-on user.

  • AppEvents: Settings for assigned sounds to play for system and applications sound events.
  • Control Panel: Control Panel settings, similar to those defined in System.ini, Win.ini and Control.ini in Windows 3.xx.
    • Desktop
      • MaxMinClose: (0 or 1) Set to 0 to disable the max/min/close tooltips.
      • MenuShowDelay: (delay in ms 0-999) The delay between clicking the menu/right clicking and the menu appearing, it is useful to set this to 0.
      • CoolSwitchColumns: Configure number of columns in the Alt-Tab Task Switcher
      • CoolSwitchRows: Configure number of rows in the Alt-Tab Task Switcher
      • WindowMetrics
        • MinAnimate: (string value: 0 or 1) Allows you to disable the title-bar animation when you minimise a window.
        • "Shell Icon BPP: (no of bytes as string) This key details the bit-depth (number of colours) for the icons. In nearly all cases this should equal the bit-depth of your screen. If this setting is too high Windows will default to 4 bit/16 colour icons. See also: Icon problem: Low colour icons (4 bits/16 colours) even with 16/32 bit screen mode (Windows)
  • InstallLocationsMRU: Contains the paths for the Startup folder programs.
  • Keyboard layout: Specifies current keyboard layout.
  • Network: Network connection information.
  • RemoteAccess: Current log-on location information, if using Dial-Up Networking.
  • Policies
    • Microsoft\\Internet Explorer\\Control Panel: This key allow restrictions in editing settingsInternet Explorer settings. For each key below 0=user can edit settings, 1=appears ghosted/unavailable. All are DWORD.
      • HomePage: Restrict change of home page
      • Cache: Restrict changes to temporary Internet files
      • History: Restrict changes to history settings
      • Colors: Restrict changing of colour settings
      • Fonts: Restrict font settings
      • Accessibility: Restrict accessibility settings
      • Profiles: Restrict changes to profiles
      • Proxy: Restrict the changing of the proxy.
      • Autoconfig: Disable autoconfig
      • Advanced: Restrict advanced settings; does not remove tab.
      • ConnWiz Admin Lock: Disable connection wizard
      • SecurityTab: Hides Security tab in Settings.
      • AdvancedTab: Hides Advanced tab in Settings.
      • ConnectionsTab: Hides Connections tab in Settings.
      • ProgramsTab: Hides Programs tab in Settings.
  • Software: Software configuration settings for the currently logged-on user.
    • Microsoft
      • Command Processor
        • DisableUNCCheck (0 or 1) Allow UNC paths to be used in commands.
      • Office\\<9.0|10.0|11.0>
        • Word\\Options
          • SQLSecurityCheck: (0 or 1) Set this to 0 to disable the "Opening this document will run the following SQL command" prompt when opeing the Word doc that runs a SQL query.
        • Outlook\\Security
    • Microsoft\\Windows\\CurrentVersion
      • Policies
        • Explorer
          • NoResolveTrack: (0 or 1) If a shortcut is broken when double-clicked Windows will try to find it be default; set to 1 to disable this feature.
          • NoInternetIcon: (0= IE icon appears on desktop 1=IE icon not on desktop) SK/UK
          • NoSMConfigurePrograms: (0 or 1) Set to 1 to remove to remove the Set Program Access and Defaults icon on the start menu. SK/UK
          • MaxRecentDocs: (no of documents as DWORD) The setting dictates the number of documents to be displayed in Recent Documents. SK/UK
      • Internet Settings
        • ProxyServer: Address for a proxy server for the Internet API
        • ProxyEnable: (0 or 1)
        • ProxyOveride: Excluded addreses
      • Explorer
        • link: (binary) 00 00 00 00 = no "Shortcut to" prefix on shortuts. SK/UK
        • StuckRects: This key includes information relating to the taskbar. If the taskbar is not working for some reason this key can be deleted to revert it to its default values.
        • Desktop
          • DesktopProcess: (1=seperate process 0=default) Windows will normally use the same process for the Desktop, takebar and directory-windows. Should any one of these crash then the taskbar and Desktop will need to restart as well. Setthis key to 1 to put your desktop and taskbar in a seperate process. Note: Active Desktop, IE pre 5.5 cannot be used with this key set to 1.
          • CleanupWiz
            • "Days between clean up"
            • NoRun: (0 or 1) Set to disable the desktop cleanup wizard
        • Shell Folders
        • User Shell Folders
        • Advanced
          • Hidden (1 = show 2 = do not show) Display hidden files.
          • ShowSuperHidden: (0 = hide files 1= show files) As above but for files when are hidden and system.
          • Intellimenus: (0 or 1) Set to 0 to disable the hiding of rarely used menu items until you select the down-arrows.
          • StartMenuScrollPrograms ("yes" or "no") Allow scrolling of programs in the start menu.
          • EnableBalloonTips: (0 or 1) Set to 0 to disable balloon tips for example print notifications and the tour.
          • TaskbarSizeMove: (0 = locked 1 = unlocked) If context menus on the start menu have been disabled than the start menu position can still be locked/unlocked with this key.
          • TaskbarGlomming: (0 = not groups/Win2k style 1 = grouped) This key controls taskbar item grouping.
          • NoTrayContextMenu: (0 = disabled 1 = enabled) This key controls context menus for the start menu.
        • CabinetState
          • "Use Search Asst": Set to "no" to enable the Win2k search interface, inculde the spaces in the key name.
        • RunMRU: The cached entries for Run commands in the start menu are stored hereandcan be safely deleted if required.
  • Microsoft\\Windows CE Services\\Partners\\ \\\\Services\\\\Synchronization: Settings in realtion to PDAs/smartphone, typically with regard to ActiveSync. Note the US spelling.
    • Briefcase Creation: States when the synchronisation was setup in seconds from 12:00 AM 0/0/0
    • ResetPartner: (0 or 1) Set to 1 to force the reset of a partnership.
    • Windows NT\\Curent Version
      • Program Manager\\Restrictions: Allows manipulation restrictions; usually set by Group Policy.
        • NoRun: (0 or 1)
        • NoFileMenu: (0 or 1)
        • NoClose: (0 or 1)
      • Winlogon
        • BuildNumber: You can have great fun with this if you are bored.
        • ParseAutoexec: Force Windows to parse the autoexec.bat file.

HKEY_LOCAL_MACHINE

Contains information about the hardware and software settings that are generic to all users of this particular computer.

  • Hardware: Information regarding hardware of the system, populated by NTDETECT.COM, loaded by NTLDR, at the very beginning of the boot process.
  • Security: Network security settings.
  • Software: Software specific information/settings, often by make first
    • Microsoft
      • Security Center
        • AntiVirusDisableNotify: (0 or 1) Set to 1 to disable 'Your computer might be at risk alerts' in XP SP2 for not having detectable AV installed. See: Disable Security Center Alerts (Tacktech)
        • FirewallDisableNotify: (0 or 1) As above toy firewall.
        • UpdatesDisableNotify: (0 or 1) As above for not enabling automatic updates.
      • Windows\\CurrentVersion
        • ProgramFilesDir: Change the default dir for new programs here.
        • Sourcepath: (string) Windows uses this key or the one under the Setup key below as a source for the Windows CD. Copy your i386 dir on your Windows CD and set this key accordingly and you will no longer have to insert your Windows CD when Windows requires files from it.
        • Policies\\Ratings
        • Setup
          • Sourcepath: (string) Some apps use the key here instead of the one detailed above; set both to reflect you i386 folder location.
        • CommonFilesDir: Location of the Common files dir. Default is c:\\program files\\Common files
        • Netcache: Settings relating to offline folders; entries here are often put there by Group Policy in Computer Configuration\\Administrative Templates\\Network\\Offline Files folder.
          • Enabled: (0 or 1) Disables or enables and restricts the user from changing the setting.
          • NoCacheViewer: (0 or 1) Disables the 'Offline Files' folder although it is still enabled through using the network drives offline.
          • NoReminders: (0 or 1) Disables reminders to synchronise. Ensure this is set to 1 if you have it disabled it via editing the registry - it can cause problems otherwise.
          • FormatDatabase: (1) If there is corruption in the offline files/CSC database and the Offline Files tab cannot be accesed, create this key. The actual value is ignored; upon rebooting Windows will clear the CSC database and del the key.
        • DateTime\\Servers: Time server for synchronising your time are set here, use sub-keys with the names or 1,2,3, etc to set preference.
    • Explorer
      • Desktop\\NameSpace: Listed here GUIDS for CLASS IDs for icons/functions to appear on the Desktop. These are usually used by Windows itself, for example My Documents is listed here. See also: Create custom System Folder on Desktop/My Computer (Windows)
      • MyComputer\\Namespace: Listed here GUIDS for CLASS IDs for icons/functions to appear within My Compurer. For example Control Panel has an entry here. See also: Create custom System Folder on Desktop/My Computer (Windows)
      • EnableBalloonTips: (0 or 1)
      • FolderContentsInfoTip: (0 or 1) Disable folder stats on mouse hover.
      • StartButtonBalloonTip: (0 or 1) Disable Start Menu mouse hover tips.
      • InternetOpenWith: (0 or 1) Allows the disabling of the web service dialogue when a file of an unknown type is opened - opening with Open With dialog instead. SK/UK
      • PersistBrowsers: (0 or 1) With this enabled Windows will reopen and directories that were open when shutting down. - A little like session saving for directory listings only.
      • ThumbnailSize: (height in pixels) This settings specifies the size of the thumbnails in the thumbnail view - this is useful if you have a large screen resolution and your thumbnails are too small. Windows may need to be restarted for the changes make to take effect.
      • ThumbnailQuality: (percent) Setting this will decrease the thumbnail size by (100-thumbnail_quality)% and blow it up to the size in the ThumbnailSize key. Pixelation is blurred.
      • AlwaysUnloadDLL: (0 or 1) Windows caches DLLs in use by a programme after it has quit for a while. It benefit is lost on low-memory for heavy-load systems, disable it by setting the key to 1.
    • Policies:
      • DontDisplayLastUserName: (0 or 1) Set this to 1 and upon relogging in the last user name to do will not be shown.
      • VerboseStatus: (0 or 1) When enabled this will show verbose information when logging on or off or booting up or shutting down. Useful for diagnosing slow startups.
      • Explorer:
        • ClassicShell: (0 or 1) Set to 1 to disable most of the Windows 98+ features in Explorer. Features including Active Desktop, Web & thumbnail views will be disabled. SK/UK
        • NoDriveTypeAutoRun: dword:000000ff Disable autorun for CDs.
        • NoSaveSettings: (0 or 1) Check this key if your profile is not saving, or use it under HKCU for a standardised login/layout.
        • MemCheckBoxInRunDlg: (0 or 1) Show the run in separate memory space option in the run dialog box. This is useful if you find your 16-bit apps have never run properly from Win2k onwards as running the virtual DOS machine in sandbox mode might allow it run properly.
    • OptimalLayout
      • EnableAutoLayout: (0 or 1) Auto moves data on your disk when idle so that frequently used drivers/programmes are quicker to access.
    • Microsoft\\Windows CE Services: Settings in relation to PDAs/smartphone, typically with regard to ActiveSync.
      • GuestOnly: (0 or 1) Set to 1 to disable the ability to create new partnerships.
      • AppMgr
        • SilentInstall: (0 or 1) Set to 0 to stop the ActiveSync installing whenever the device is connected, also delete the key below:
      • AutoStartOnConnect
        • CEAppMgr: (string) Use this key if you wish to set a third-party app back to use the PDA/smartphone after ActiveSync has installed itself over the top.
    • Microsoft\\Windows NT\\CurrentVersion
      • Setup
        • Diagnostics: Read this if you intend to apply these keys to Windows Server 2003: MS KB 889088
          • RunDiagnosticLoggingGlobal: Enable user environment event logging
          • RunDiagnosticLoggingGroupPolicy: Enable event logging for group policies only
          • RunDiagnosticLoggingAppDeploy: Enable event logging for GPO application deployment only
          • RunDiagnosticLoggingIntelliMirror: Enable event logging for remote boot only
        • RecoveryConsole
          • SetCommand: (0=disallow 1=allow) Allow access to HDs and floppy drive from the recovery console.
      • Winlogon
        • PasswordExpiryWarning: (no of days in DWORD)
        • LogonType: (0 or 1) This value is 0 by default for Win2k/XP Pro and 1 for XP Home. If you have XP Home but miss the Ctrl+Alt+Del functions of XP Pro then this is a good key to know.
        • AllowMultipleTSSessions: (0 or 1) Enables fast user switching thus without having to close any programmes.
        • Welcome: (string) Use this key to append text to the end of the logon and security dialog titles.
        • ForceAutoLogon: (0 or 1) With the auto logon feature enabled it can be disabled on a per-session basis my holding shift - this key disables that ability.
        • LegalNoticeText: (string) create a dialog box before logging on that the users have to click past, whch can be used for legal notices but is also used for system announcements in some environments.
        • LegalNoticeCaption: (string) Set the title for the legal notice window.
        • ScreenSaverGracePeriod: (string in seconds) This setting determines how many seconds after the screensaver appears that the machine should be locked if it is enabled.
        • UserEnvDebugLevel: Enable the verbose logging of user profile and other processes for troubleshooting. The resulting log file is in %SystemRoot%\\Debug\\UserMode\\Userenv.log .
      • WPAEvents
        • OOBETimer: (binary) This key is a hash of your Windows product key. Tools which can read the product key on your PC decode this. Change one of the values in this key to deactivate Windows to allow a new key to be entered. See also: Change Product Key (Windows XP)
    • Policies:
      • System
        • ReadOnlyProfile: (0 or 1) Disables the saving of the profile.
  • System: Contains information on which device drivers should be loaded at startup, it is populated from systemroot\\System32\\Config\\System. NTLDR uses this hive to ascertain which device drivers need to be loaded during startup. Each configuration of device drivers is stored under ControlSetxxx. Other subkeys include:
    • CurrentControlSet: A pointer to a ControlSetxxx - the one currently in use.
      • Control
        • FileSystem
          • NtfsDisable8dot3NameCreation: (0 or 1) 2000/XP still creates 8dot3 filenames for backwards compatibility with apps that do not support Windows 95+. If none of your apps are that old set this key to 1 to improve performance.
          • NtfsDisableLastAccessUpdate: (0 or 1) Disable updating of the last accessed timestamp to improve performance. Updating of other timestamps is unaffected.
        • Class\\{36FC9E60-C465-11CF-8056-444553540000}\\0000
          • IdleEnable: (0 or 1) Set this to one to increase the USB polling interval. This is useful for laptops as it allows a better standby.
        • Terminal Server
      • Session Manager
        • SafeDllSearchMode: Change the search order for a required DLL for a programme. 1 = search Windows dirs first, 0 = current dir first.
        • Memory Management
          • SystemPages: This key relfects the number of page table entries, if you find your system is crashing under heavy I/O loads this could fix it.
          • DisablePagingExecutive: (0 or 1) Systems with a large amount of RAM can easily increase system performance by forcing Windows to not page its core systems - the Windows Executive.
          • ClearPageFileAtShutdown: (0 or 1) Heavy load systems will benefit from a fresh page file and it makes it harder for hackers to try and mine passwords from it.
          • LargeSystemCache: (DWORD 0=desktops 1=servers) Control the memory dedicated for file caching. Desktops tend to be optimal when more memory is for apps - the reverse is true for servers although setting this value to 1 on a desktop could speed it up.
        • Subsystems
          • Optional: The session manager loads OS/2 and Posix when they are rarely used. You can disable both sub systems from removing "Posix" from the key. Leave "OS/2" in the key if it is there.
    • Services
      • Tcpip
        • Parameters
          • DisableTaskOffload: (0 or 1) Set this to 0 to use the CPU within your NIC if it has one; this slightly reduces the load on your CPU.
    • Select: Information on which ControlSet is chosen when:
      • Default: The CS that will be used/attempted on the next bootup
      • Current
      • Failed: If 0 then no fail has ever occured - otherwise this states a config that has previously failed.
      • LastKnownGood: Points to the CS that was used during the last user session.

HKEY_USERS

Contains all user profiles stored by their SID, you should only require use of this key if you want to edit the registry of a user whilst not logged on as the user. HKEY_CURRENT_USER points to the SID of the user currently logged on and HKEY_CLASSES_ROOT points to the "\_Classes\" key (along with HKEY\_LOCAL\_MACHINE\\\\SOFTWARE\\\\Classes.)

  • .DEFAULT: The profile windows uses at the login prompt/GINA chain and the default profile when new users are created.

See Also

Category:Windows