Internet Explorer Registry API

As with any large program, Internet Explorer has many registry settings. Some are used so widely within Internet Explorer that Microsoft has developed library code to standardise their handling. In Windows Vista, this library code is statically linked into approximately a dozen executables. Version 8.0 has dynamic linking to functions that are exported from IERTUTIL:

• IERegDeleteValue
• IERegEnumKeys
• IERegEnumValues
• IERegGetBool
• IERegGetBoolEx
• IERegGetBufferSizeSz
• IERegGetBufferSizeTz
• IERegGetBufferSizeWz
• IERegGetDw
• IERegGetDwEx
• IERegGetSz
• IERegGetSzEx
• IERegGetTz
• IERegGetTzEx
• IERegGetWz
• IERegGetWzEx
• IERegResolve
• IERegSetDw
• IERegSetSz
• IERegSetTz
• IERegSetWz

Each function takes as its first argument an index that represents an Internet Explorer registry setting. There is also a common set of possible error codes:

Preference and Policy Branches

Each setting may be stored at the same position relative to as many as four keys depending on whether it is to represent a user’s preference or be imposed by administrative policy. The following table lists these keys in order of decreasing precedence.

The merit in reproducing a value in multiple locations lies in the combination of applicability and access. A setting in either of the HKEY_LOCAL_MACHINE branches is intended for all users, but the same setting in either of the HKEY_CURRENT_USER branches is meant just for the current user. Indeed, what the system presents as HKEY_CURRENT_USER is different for different users. A setting that is stored beneath either of the Software\Policies keys or in either of the HKEY_LOCAL_MACHINE branches typically cannot be modified except with administrative privilege.

The first branch therefore sets a machine-wide policy, with no exception. The second branch allows an administrator to write different policies for particular users, but the machine-wide policy has precedence. Though a user can typically write the setting in the HKEY_CURRENT_USER\Software key, there may be no effect since all policies apply before all preferences. Note the reversal of machine and user branches in moving from policies to preferences. The last branch also applies machine-wide, like the first, but it has little force: users are free to override it in their HKEY_CURRENT_USER\Software branch.

Not all settings are recognised in all locations. The functions read a setting by iterating through the setting’s allowed locations in order of decreasing precedence and accepting whatever is found first. Each setting has an expected type. If a registry value is found for a setting but does not have the expected type, it is ignored. Some settings are defined with a default, some not. The functions for reading a setting generally do not care which of the allowed locations a setting is found from or whether the setting is defaulted. The functions that write or delete a setting operate only in the preference branches.

The Supported Settings

In the IERTUTIL from Windows 7, there are 83 of these common registry settings. All are recognised in at least one of the Policies branches, so that they are all settable as policies. Most are recognised in all four branches, so that they can also be set as preferences.

As policies, most have user-interface support through the INETRES.ADMX administrative template loaded by the Group Policy Object Editor. Bear in mind that for the Group Policy Object Editor, settings are always policies. They are described from the perspective of an administrator forcing some behaviour, not of a user exercising a preference. For rather many, the text in the administrative template seems to be the whole of Microsoft’s documentation, not just of the registry implementation but even of the corresponding feature.

The DaysToKeep setting has user-interface support through Internet Properties in the Control Panel, as “Days to keep pages in history” in the “Temporary Internet Files and History Settings” dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Days to keep pages in History” in the Properties for

Disable “Configuring History”

in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The ProxyServer setting has no known user-interface support.

The AutoSuggest setting has user-interface support through the Group Policy Object Editor, as “Turn off the auto-complete feature for web addresses” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The Use FormSuggest setting has user-interface support through the Group Policy Object Editor, as “Disable AutoComplete for forms” in the Internet Expolorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The FormSuggest Passwords setting has user-interface support through the Group Policy Object Editor, as “Turn on the auto-complete feature for user names and passwords on forms” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The FormSuggest Pw Ask setting has user-interface support through the Group Policy Object Editor, as the “Prompt me to save passwords” checkbox in the Properties for “Turn on the auto-complete feature for user names and passwords on forms” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The Start Page value has user-interface support through Internet Properties in the Home Page edit box on the General tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as the Home Page textbox in the Properties for “Disable changing home page settings” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The DisableCustomerImprovementProgram setting has user-interface support through the Group Policy Object Editor, as “Prevent participation in the Customer Experience Improvement Program” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0” and be “not supported on Windows Vista”.

The DisableDeleteBrowsingHistory setting has user-interface support through the Group Policy Object Editor, as

Turn off “Delete Browsing History” functionality

in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The BackgroundSyncStatus setting has user-interface support through the Group Policy Object Editor, as “Turn off background sync for feeds” in the RSS Feeds administrative template (shown under Windows Components). It is there said to require “at least Internet Explorer 7.0”.

The Enabled setting has user-interface support through the Group Policy Object Editor, as “Turn off feed discovery” in the RSS Feeds administrative template (shown under Windows Components). It is there said to require “at least Internet Explorer 7.0”.

The DisableFeedPane setting has user-interface support through the Group Policy Object Editor, as “Turn off the feed list” in the RSS Feeds administrative template (shown under Windows Components). It is there said to require “at least Internet Explorer 7.0”.

The DisableAddRemove setting has user-interface support through the Group Policy Object Editor, as “Turn off addition and removal of feeds” in the RSS Feeds administrative template (shown under Windows Components). It is there said to require “at least Internet Explorer 7.0”.

The DisableEnclosureDownload setting has user-interface support through the Group Policy Object Editor, as “Turn off downloading of enclosures” in the RSS Feeds administrative template (shown under Windows Components). It is there said to require “at least Internet Explorer 7.0”.

The PreventIgnoreCertErrors setting has user-interface support through the Group Policy Object Editor, as “Prevent ignoring certificate errors” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Enabled setting has user-interface support through the Group Policy Object Editor, as “Turn off Profile Assistant” in the Advanced Page category (shown under Internet Control Panel) of the Internet Explorer administrative template. It is there said to require “only Internet Explorer 6.0 in Windows 2003 Service Pack 1”. Note that the user interface inverts the setting: enabling the setting, i.e., to turn off the Profile Assistant, sets 0 as the data for the registry value.

The Update_Check_Interval setting has user-interface support through the Group Policy Object Editor, as the “Update check interval (in days)” textbox in the Properties for “Turn off configuring the update check interval (in days)” in the “Periodic check for updates to Internet Explorer and Internet Tools” category (shown under Component Updates, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template enforces the range 1 to 365 inclusive.

The Update_Check_Page setting has user-interface support through the Group Policy Object Editor, as the “URL to be displayed for updates” textbox in the Properties for “Turn off changing the URL to be displayed for checking updates to Internet Explorer and Internet Tools” in the “Periodic check for updates to Internet Explorer and Internet Tools” category (shown under Component Updates, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template’s suggestion for the value is “http://www.microsoft.com/isapi/redir.dll?Prd=ie&Pver=5.0&Ar=ie5update”.

The IEAKUpdateUrl setting has user-interface support through the Group Policy Object Editor, as the Cipher Strength Update Information URL textbox in the Properties for “Prevent the configuration of cipher strength update information URLs” in the “Help Menu > About Internet Explorer” category (shown under Component Updates, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template’s suggestion for the value is “http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=128bit”.

The UrlEncoding setting has user-interface support through the Group Policy Object Editor, as “Turn off sending URLs as UTF-8 (requires restart)” in the URL Encoding category (shown under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The DisableICW setting has user-interface support through the Group Policy Object Editor, as “Turn on the Internet Connection Wizard Auto Detect” in the Internet Connection Wizard Settings category (shown under “Advanced settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0” but be “not supported on Windows Vista”.

The Friendly http errors setting has user-interface support through the Group Policy Object Editor, as “Turn off friendly http error messages” in the Browsing category (shown under “Advanced settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Error Dlg Displayed On Every Error setting has user-interface support through the Group Policy Object Editor, as “Turn on the display of a notification about every script error” in the Browsing category (shown under “Advanced settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Use_DlgBox_Colors setting has user-interface support through Internet Properties, as “Use Windows colors” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent the use of Windows colors” in the General Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Text Color setting has user-interface support through Internet Properties, as “Text” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as the “Text color” textbox in the Properties for “Prevent users from configuring text color” in the General Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template describes the string data as comma-separated decimals making an RGB value, and suggests “0,0,0”.

The Background Color setting has user-interface support through Internet Properties, as “Background” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as the “Background color” textbox in the Properties for “Prevent users from configuring background color” in the General Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template describes the string data as comma-separated decimals making an RGB value, and suggests “192,192,192”.

The Anchor Color Visited setting has user-interface support through Internet Properties, as “Visited” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as the “Visited link color” textbox in the Properties for “Prevent users from configuring the color of links that have already been clicked” in the Link Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template describes the string data as comma-separated decimals making an RGB value, and suggests “96,100,32”.

The Anchor Color setting has user-interface support through Internet Properties, as “Unvisited” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as the “Link color” textbox in the Properties for “Prevent users from configuring the color of links that have not yet been clicked” in the Link Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template describes the string data as comma-separated decimals making an RGB value, and suggests “0,0,255”.

The Anchor Color Hover setting has user-interface support through Internet Properties, as “Hover” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as the “Hover color” textbox in the Properties for “Prevent users from configuring the hover color” in the Link Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template describes the string data as comma-separated decimals making an RGB value, and suggests “255,0,0”.

The Use Anchor Hover Color setting has user-interface support through Internet Properties, as “Use hover color” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through through the Group Policy Object Editor, as “Turn on the hover color option” in the Link Colors category (shown under “Display settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Use AutoComplete setting has user-interface support through the Group Policy Object Editor, as “Turn off inline AutoComplete in Windows Explorer” in the AutoComplete category (shown under Internet Settings) of the Internet Explorer administrative template. It is there said to require “only Internet Explorer 4.0”.

The Append Completion setting has user-interface support through the Group Policy Object Editor, as “Turn on inline AutoComplete for Web addresses” in the AutoComplete category (shown under Internet Settings) of the Internet Explorer administrative template. It is there said to require “only Internet Explorer 4.0”.

The AutoSearch setting has user-interface support through the Group Policy Object Editor, as the “When searching from the address bar” dropbox in the Properties for “Prevent configuration of search from the Address bar” in the Searching category (shown under “Advanced settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template offers two interpretations:

• 0, meaning “Do not search from the address bar”
• 4, meaning “Just display the results in the main window”

The ForceCodeDownloadLog setting has no known user-interface support.

The CodeBaseSearchPath setting has user-interface support through the Group Policy Object Editor, as the Path textbox in the Properties for “Prevent setting of the code download path for each machine” in the Code Download category (shown under Corporate Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template’s suggestion for the value is “CODEBASE;<http://activex.microsoft.com/objects/ocget.dll>” as the string data.

The Display Inline Images setting has user-interface support through Internet Properties, as “Show pictures” in the Multimedia gropu on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off picture display” in the Multimedia category (shown under “Advanced settings”, in turn under Internet Settings) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Connection Settings setting has user-interface support through the Group Policy Object Editor, as “Disable changing connection settings” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The Connwiz Admin Lock setting has user-interface support through the Group Policy Object Editor, as “Disable Internet Connection Wizard” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”. The administrative template offers only the per-user policy. The machine-wide policy is instead absorbed into “Disable changing connection settings”, such that enabling the policy, i.e., disabling users from changing connection settings, sets both Connection Settings and Connwiz Admin Lock to 1.

The AutoConfig setting has user-interface support through the Group Policy Object Editor, as “Disable changing Automatic Configuration settings” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The Proxy setting has user-interface support through the Group Policy Object Editor, as “Disable changing proxy settings” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The DisableSecuritySettingsCheck setting has user-interface support through the Group Policy Object Editor, as “Turn off the Security Settings Check feature” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The DisableFixSecuritySettings setting has user-interface support through the Group Policy Object Editor, as

Prevent “Fix Settings” functionality

in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The Version setting has user-interface support through the Group Policy Object Editor, as the “Enter IE Version String” textbox in the Properties for Customize User Agent String in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template requires a non-empty string, without offering a suggestion.

The DisableRIED setting has user-interface support through the Group Policy Object Editor, as “Do not allow resetting Internet Explorer settings” in the Advanced Page category (shown under Internet Control Panel) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The History setting has user-interface support through the Group Policy Object Editor, as

Disable “Configuring History”

in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The Settings setting has user-interface support through the Group Policy Object Editor, as “Prevent the deletion of temporary Internet files and cookies” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The DisableDeleteForms setting has user-interface support through the Group Policy Object Editor, as

Turn off “Delete Forms” functionality

in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The DisableDeletePasswords setting has user-interface support through the Group Policy Object Editor, as

Turn off “Delete Passwords” functionality

in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The EnableSearchPane setting has no known user-interface support.

The AutoDetect setting has user-interface support through the Group Policy Object Editor, as “Turn on automatic detection of the intranet” in the Security Page category (shown under Internet Control Panel) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The IntranetName setting has user-interface support through the Group Policy Object Editor, as “Intranet Sites: Include all local (intranet) sites not listed in other zones” in the Security Page category (shown under Internet Control Panel) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 6.0 in Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1”.

The ProxyByPass setting has user-interface support through the Group Policy Object Editor, as “Intranet Sites: Include all sites that bypass the proxy server” in the Security Page category (shown under Internet Control Panel) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 6.0 in Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1”.

The UNCAsIntranet setting has user-interface support through the Group Policy Object Editor, as “Intranet Sites: Include all network paths (UNCs)” in the Security Page category (shown under Internet Control Panel) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 6.0 in Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1”.

The GeneralTab setting has user-interface support through the Group Policy Object Editor, as “Disable the General page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The SecurityTab setting has user-interface support through the Group Policy Object Editor, as “Disable the Security page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The PrivacyTab setting has user-interface support through the Group Policy Object Editor, as “Disable the Privacy page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The ContentTab setting has user-interface support through the Group Policy Object Editor, as “Disable the Content page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The ConnectionsTab setting has user-interface support through the Group Policy Object Editor, as “Disable the Connections page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The ProgramsTab setting has user-interface support through the Group Policy Object Editor, as “Disable the Programs page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The AdvancedTab setting has user-interface support through the Group Policy Object Editor, as “Disable the Advanced page” in the Internet Control Panel category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

The RestrictPopupExceptionList setting has user-interface support through the Group Policy Object Editor, as “Turn off Managing Pop-up Allow list” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The DisablePopupFilterLevel setting has user-interface support through the Group Policy Object Editor, as “Turn off managing Pop-up filter level” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

RESOLUTION OF PLACEHOLDER YET TO BE DESCRIBED

The Flags setting has no known user-interface support.

RESOLUTION OF PLACEHOLDER YET TO BE DESCRIBED

The Info setting has no known user-interface support.

The NoNavBar setting has user-interface support through the Group Policy Object Editor, as Enforce Full Screen Mode in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

This setting is just one of several involved in what the administrative template describes as enforcing full-screen mode: both NoNavBar and NoCommandBar are set to 1, and AlwaysShowMenus to 0.

The NoCommandBar setting has user-interface support through the Group Policy Object Editor, as Enforce Full Screen Mode in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

This setting is just one of several involved in what the administrative template describes as enforcing full-screen mode: both NoNavBar and NoCommandBar are set to 1, and AlwaysShowMenus to 0.

The Flags setting has no known user-interface support.

SUBKEY ENUMERATION YET TO BE DESCRIBED

This setting has no known user-interface support.

SUBKEY ENUMERATION YET TO BE DESCRIBED

This setting has no known user-interface support.

SUBKEY ENUMERATION YET TO BE DESCRIBED

 This setting has no known user-interface support.

The IEFontSize setting has user-interface support through the Group Policy Object Editor, as the Default Size dropbox in the Properties for “Prevent users from choosing default text size” in the “Display settings” category (shown under “Internet settings”) of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template sets the data according to the following scheme:

• 0 for Smallest;
• 1 for Smaller;
• 2 for Medium;
• 3 for Larger;
• 4 for Largest.

The ProxySettingsPerUser setting has user-interface support through the Group Policy Object Editor, as “Make proxy settings per-machine (rather than per-user)” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 5.0”.

VALUE ENUMERATION YET TO BE DESCRIBED

This setting has user-interface support through the Group Policy Object Editor, as “Enter the list of sites here” in the Properties for “Pop-up allow list” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 6.0 in Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1”.

The DisableFirstRunCustomize setting has user-interface support through the Group Policy Object Editor, as “Prevent performance of First Run Customize settings” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”. The administrative template sets the data according to the following scheme:

• 1, to go directly to the home page,
• 2, to go directly to the “Welcome To IE” page.

The DisableToolbarUpgrader setting has user-interface support through the Group Policy Object Editor, as “Turn off toolbar upgrade tool” in the Toolbars category of the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 7.0”.

The ProtectedModeOffForAllZones setting has no known user-interface support.

SUBKEY ENUMERATION YET TO BE DESCRIBED

VALUE ENUMERATION YET TO BE DESCRIBED

The TotalLimit setting has no known user-interface support.

The DomainLimit setting has no known user-interface support.

The OnlyUseAXISforActiveXInstall setting has user-interface support through the Group Policy Object Editor, as “Only use the ActiveX Installer Service for installation of ActiveX Controls” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 8.0”.

The BlockNonAdminActiveXInstall setting has user-interface support through the Group Policy Object Editor, as “Disable Per-User Installation of ActiveX Controls” in the Internet Explorer administrative template. It is there said to require “at least Internet Explorer 8.0”.

The AllowList setting has no known user-interface support.