IE10 User-Agent causes ASP.Net to not send back Set-Cookie (IE10 not setting cookies)

 IE10 is a cookieless browser (i.e. cant support cookies). In our problem case the server was setting the authentication cookie and sending it back to the browser,

<authentication mode="Forms">
  <forms name=".AUTH" cookieless="UseCookies" loginUrl="/" timeout="10000" path="/" />
</authentication>

Better to Add for some more IE10 browser Compatibility.

In the meantime to make it work and to avoid similar issues in the future, I use a file ~\App_Browsers\BrowserFile.browser with the following:

<browsers>
<browser refID="Default">
<capabilities><!-- To avoid wrong detections of e.g. IE10 -->
<capability name="cookies" value="true" />
<capability name="ecmascriptversion" value="3.0" />
</capabilities>
</browser>
</browsers>