cefsharp/CefSharp · error · ObjectDisposedException

CookieManager

Error message

CookieManager

What it means

DeleteCookiesAsync is an extension method on ICookieManager. If the manager's IsDisposed property is true — meaning the cookie manager (and typically its owning browser or context) has already been torn down — the call throws ObjectDisposedException before attempting the delete.

Source

Thrown at CefSharp/AsyncExtensions.cs:34

        /// <summary>
        /// Deletes all cookies that matches all the provided parameters asynchronously.
        /// If both <paramref name="url"/> and <paramref name="name"/> are empty, all cookies will be deleted.
        /// </summary>
        /// <param name="cookieManager">cookie manager</param>
        /// <param name="url">The cookie URL. If an empty string is provided, any URL will be matched.</param>
        /// <param name="name">The name of the cookie. If an empty string is provided, any URL will be matched.</param>
        /// <returns>Returns -1 if a non-empty invalid URL is specified, or if cookies cannot be accessed;
        /// otherwise, a task that represents the delete operation. The value of the TResult will be the number of cookies that were deleted or -1 if unknown.</returns>
        public static Task<int> DeleteCookiesAsync(this ICookieManager cookieManager, string url = null, string name = null)
        {
            if (cookieManager == null)
            {
                throw new ArgumentNullException(nameof(cookieManager));
            }

            if (cookieManager.IsDisposed)
            {
                throw new ObjectDisposedException("CookieManager");
            }

            var callback = new TaskDeleteCookiesCallback();
            if (cookieManager.DeleteCookies(url, name, callback))
            {
                return callback.Task;
            }

            //There was a problem deleting cookies
            return Task.FromResult(TaskDeleteCookiesCallback.InvalidNoOfCookiesDeleted);
        }

        /// <summary>
        /// Sets a cookie given a valid URL and explicit user-provided cookie attributes.
        /// This function expects each attribute to be well-formed. It will check for disallowed
        /// characters (e.g. the ';' character is disallowed within the cookie value attribute) and will return false without setting
        /// </summary>
        /// <param name="cookieManager">cookie manager</param>

View on GitHub (pinned to 16bc6e0711)

Solutions

1. Check cookieManager.IsDisposed before calling DeleteCookiesAsync.
2. Cancel in-flight cookie operations when the browser is closing (use a CancellationToken or a completion gate).
3. Obtain a fresh ICookieManager reference from the live browser/RequestContext rather than caching it long-term.

Example fix

// before — manager may be disposed
await cookieManager.DeleteCookiesAsync("https://example.com", null);

// after — guard before call
if (cookieManager == null || cookieManager.IsDisposed)
    return;
await cookieManager.DeleteCookiesAsync("https://example.com", null);

if (cookieManager == null || cookieManager.IsDisposed)
{
    return Task.FromResult(TaskDeleteCookiesCallback.InvalidNoOfCookiesDeleted);
}
return cookieManager.DeleteCookiesAsync(url, name);

try
{
    await cookieManager.DeleteCookiesAsync(url, name);
}
catch (ObjectDisposedException)
{
    Log.Info("CookieManager disposed — skipping delete");
}

When it happens

Trigger: Calling DeleteCookiesAsync on a cookie manager obtained from a disposed browser, a disposed RequestContext, or the global manager after Cef.Shutdown.

Common situations: Awaited async cookie operations completing after the browser window was closed. Using a cached ICookieManager reference that outlived its browser. Cleanup ordering: browser disposed while cookie tasks are still in-flight.

Related errors

• IBrowser
• Browser has been disposed
• frame
• Expected Exception
• The ChromiumWebBrowser instance creates the underlying Chrom

AI-assisted analysis of cefsharp/CefSharp@16bc6e0711 (2026-08-13). Data as JSON: /api/errors/b3c6258767eb5d74. Report an issue: GitHub.