Use browserExecutableFolder to specify whether WebView2 controls use a fixed or installed version of the WebView2 Runtime that exists on a user machine. To use a fixed version of the WebView2 Runtime, pass the folder path that contains the fixed version of the WebView2 Runtime to browserExecutableFolder. BrowserExecutableFolder supports both relative (to the application's executable) and absolute files paths. To create WebView2 controls that use the installed version of the WebView2 Runtime that exists on user machines, pass a null or empty string to browserExecutableFolder. In this scenario, the API tries to find a compatible version of the WebView2 Runtime that is installed on the user machine (first at the machine level, and then per user) using the selected channel preference. The path of fixed version of the WebView2 Runtime should not contain \Edge\Application\. When such a path is used, the API fails with HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED).

The default channel search order is the WebView2 Runtime, Beta, Dev, and Canary. When an override WEBVIEW2_RELEASE_CHANNEL_PREFERENCE environment variable or applicable releaseChannelPreference registry value is set to 1, the channel search order is reversed.

You may specify the userDataFolder to change the default user data folder location for WebView2. The path is either an absolute file path or a relative file path that is interpreted as relative to the compiled code for the current process. For UWP apps, the default user data folder is the app data folder for the package. For non-UWP apps, the default user data ({Executable File Name}.WebView2) folder is created in the same directory next to the compiled code for the app. WebView2 creation fails if the compiled code is running in a directory in which the process does not have permission to create a new directory. The app is responsible to clean up the associated user data folder when it is done.

\> [!NOTE]\n\> As a browser process may be shared among WebViews, WebView creation fails with HRESULT_FROM_WIN32(ERROR_INVALID_STATE) if the specified options does not match the options of the WebViews that are currently running in the shared browser process.

environmentCreatedHandler is the handler result to the async operation that contains the WebView2Environment that was created.

The browserExecutableFolder, userDataFolder and additionalBrowserArguments of the environmentOptions may be overridden by values either specified in environment variables or in the registry.

When creating a WebView2Environment the following environment variables are verified.

WEBVIEW2_BROWSER_EXECUTABLE_FOLDER
WEBVIEW2_USER_DATA_FOLDER
WEBVIEW2_ADDITIONAL_BROWSER_ARGUMENTS
WEBVIEW2_RELEASE_CHANNEL_PREFERENCE

If you find an override environment variable, use the browserExecutableFolder and userDataFolder values as replacements for the corresponding values in CreateCoreWebView2EnvironmentWithOptions parameters. If additionalBrowserArguments is specified in environment variable or in the registry, it is appended to the corresponding values in CreateCoreWebView2EnvironmentWithOptions parameters.

While not strictly overrides, additional environment variables may be set.

WEBVIEW2_WAIT_FOR_SCRIPT_DEBUGGER

When found with a non-empty value, this indicates that the WebView is being launched under a script debugger. In this case, the WebView issues a Page.waitForDebugger CDP command that runs the script inside the WebView to pause on launch, until a debugger issues a corresponding Runtime.runIfWaitingForDebugger CDP command to resume the runtime.

\> [!NOTE]\n\> The following environment variable does not have a registry key equivalent: WEBVIEW2_WAIT_FOR_SCRIPT_DEBUGGER.

When found with a non-empty value, it indicates that the WebView is being launched under a script debugger that also supports host apps that use multiple WebViews. The value is used as the identifier for a named pipe that is opened and written to when a new WebView is created by the host app. The payload should match the payload of the remote-debugging-port JSON target and an external debugger may use it to attach to a specific WebView instance. The format of the pipe created by the debugger should be \\.\pipe\WebView2\Debugger\{app_name}\{pipe_name}, where the following are true.

* {app_name} is the host app exe file name, for example, WebView2Example.exe * {pipe_name} is the value set for WEBVIEW2_PIPE_FOR_SCRIPT_DEBUGGER

To enable debugging of the targets identified by the JSON, you must set the WEBVIEW2_ADDITIONAL_BROWSER_ARGUMENTS environment variable to send --remote-debugging-port={port_num}, where the following is true.

* {port_num} is the port on which the CDP server binds.

\> [!WARNING]\n\> If you set both WEBVIEW2_PIPE_FOR_SCRIPT_DEBUGGER and WEBVIEW2_ADDITIONAL_BROWSER_ARGUMENTS environment variables, the WebViews hosted in your app and associated contents may exposed to 3rd party apps such as debuggers.

\> [!NOTE]\n\> The following environment variable does not have a registry key equivalent: WEBVIEW2_PIPE_FOR_SCRIPT_DEBUGGER.

If none of those environment variables exist, then the registry is examined next. The following registry values are verified.

[{Root}]\Software\Policies\Microsoft\Edge\WebView2\BrowserExecutableFolder
"{AppId}"=""

[{Root}]\Software\Policies\Microsoft\Edge\WebView2\ReleaseChannelPreference
"{AppId}"=""

[{Root}]\Software\Policies\Microsoft\Edge\WebView2\AdditionalBrowserArguments
"{AppId}"=""

[{Root}]\Software\Policies\Microsoft\Edge\WebView2\UserDataFolder
"{AppId}"=""

Use a group policy under **Administrative Templates** > **Microsoft Edge WebView2** to configure browserExecutableFolder and releaseChannelPreference.

In the unlikely scenario where some instances of WebView are open during a browser update, the deletion of the previous WebView2 Runtime may be blocked. To avoid running out of disk space, a new WebView creation fails with HRESULT_FROM_WIN32(ERROR_DISK_FULL) if it detects that too many previous WebView2 Runtime versions exist.

The default maximum number of WebView2 Runtime versions allowed is 20. To override the maximum number of the previous WebView2 Runtime versions allowed, set the value of the following environment variable.

COREWEBVIEW2_MAX_INSTANCES

If the Webview depends upon an installed WebView2 Runtime version and it is uninstalled, any subsequent creation fails with HRESULT_FROM_WIN32(ERROR_PRODUCT_UNINSTALLED).

First verify with Root as HKLM and then HKCU. AppId is first set to the Application User Model ID of the process, then if no corresponding registry key, the AppId is set to the compiled code name of the process, or if that is not a registry key then *. If an override registry key is found, use the browserExecutableFolder and userDataFolder registry values as replacements and append additionalBrowserArguments registry values for the corresponding values in CreateCoreWebView2EnvironmentWithOptions parameters.

The following summarizes the possible error values that can be returned from CreateCoreWebView2EnvironmentWithOptions and a description of why these errors occur.

Error value | Description

RPC_E_CHANGED_MODE | CoInitializeEx was previously called with COINIT_MULTITHREADED. HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED) | *\\Edge\\Application* path used in browserExecutableFolder. HRESULT_FROM_WIN32(ERROR_INVALID_STATE) | Specified options do not match the options of the WebViews that are currently running in the shared browser process. HRESULT_FROM_WIN32(ERROR_DISK_FULL) | In the unlikely scenario where some instances of WebView are open during a browser update, the deletion of the previous WebView2 Runtime may be blocked. To avoid running out of disk space, a new WebView creation fails with HRESULT_FROM_WIN32(ERROR_DISK_FULL) if it detects that too many previous WebView2 Runtime versions exist. HRESULT_FROM_WIN32(ERROR_PRODUCT_UNINSTALLED) | If the Webview depends upon an installed WebView2 Runtime version and it is uninstalled. HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND) | Could not find Edge installation. HRESULT_FROM_WIN32(ERROR_FILE_EXISTS) | User data folder cannot be created because a file with the same name already exists. E_ACCESSDENIED | Unable to create user data folder, Access Denied. E_FAIL | Edge runtime unable to start.