You can catch this on the next `Session_start` event.  If you already have an authenticated user immediately when a brand new session starts, then you must have gotten that info from a stale cookie. Just null out the user info and let Login redirects take care of the rest.  


Something like this in **`global.asax.cs`**:


    

    protected void Session_start()
    {
        // starting a session and already authenticated means we have an old cookie
        var existingUser = System.Web.HttpContext.Current.User;
        if (existingUser != null && existingUser.Identity.Name != "")
        {
            // clear any existing cookies
            IAuthenticationManager authMgr = System.Web.HttpContext.Current.GetOwinContext().Authentication;
            authMgr.SignOut("MyCookieType")

            // manually clear user from HttpContext so Authorize attr works
            System.Web.HttpContext.Current.User = new ClaimsPrincipal(new ClaimsIdentity());
        }

    }

* Code may vary somewhat depending on how you're authenticating users


See also:

* [Expire cookie at end of session OR at specific time?][1]
* [ASP.Net delete/expire session cookies][2]

[1]: https://stackoverflow.com/q/7639813/1366033
[2]: https://stackoverflow.com/q/40392596/1366033

My research indicates that, if I create a cookie and don't set the expiration date, it will expire when the browser is closed.

So I created a cookie like this:

    Response.Cookies.Set(new HttpCookie("MyKey", "X"));

But when I close the browser and then reopen it, the following expression equals true:

    Request.Cookies["MyKey"] != null

How can I have the cookie expire when the browser session ends?

*Note: For my purposes, using static data instead of a cookie seems ideal. But my understanding is that an ASP.NET can restart for a variety of reasons, and that could pull the rug out from under the current user if I lost this setting.*

Cookie to Expire when Browser Session Ends

# Update 2018 for [Microsoft Edge Developer Tools][3]

The Dev Tools in Edge finally added support for managing and browsing cookies.

> **Note**: Even if you are testing and supporting IE targets, you mine as well do the heavy lifting of your browser compatibility testing by leveraging the new tooling in Edge, and defer checking in IE 11 (etc) for the last leg.



### [Debugger Panel][4] > [Cookies Manager][6]

[![Debugger Tab][1]][1]

### [Network Panel][5] > [Request Details][7] > Cookies

[![Network Tab][2]][2]

The benefit, of course, to the debugger tab is you don't have to hunt and peck for individual cookies across multiple different and historical requests.

  [1]: https://i.stack.imgur.com/x3bGr.png
  [2]: https://i.stack.imgur.com/w1A2x.png
[3]: https://learn.microsoft.com/en-us/microsoft-edge/devtools-guide
[4]:https://learn.microsoft.com/en-us/microsoft-edge/devtools-guide/debugger
[5]: https://learn.microsoft.com/en-us/microsoft-edge/devtools-guide/network
[6]: https://learn.microsoft.com/en-us/microsoft-edge/devtools-guide/debugger/cookies
[7]: https://learn.microsoft.com/en-us/microsoft-edge/devtools-guide/network#request-details

I'm looking for how to view the cookies set using developer tools in IE11. I see an option in network profiling to view cookies being sent back and forth, but this is not really the same thing. It is cumbersome to use since it's per request. Surely there must be a way to view all cookies like you can in IE10.