The problem you have encountered has multiple causes (but is usually caused by Yahoo! Toolbar)

You’ve presumably reached this page after being told that the system isn’t sure exactly what caused your problem.  The short story is that the error reporting system isn’t perfect, and sometimes is unable to pinpoint a specific cause.  The long(er) story can be read about here.

In this particular case, the predominant reason that you’ll see this response is a problem with an older version of Yahoo! Toolbar, for which a newer version should address the failure.  You can always download the latest version of Yahoo! Toolbar here.

It’s also possible that you’ve gotten this response due to one or more other, unrelated issues.  If you’re not using Yahoo! Toolbar, but are using either the MSN Toolbar or Windows Live Toolbar, you could potentially encounter this problem as well.  You can get the latest version of MSN Toolbar here (note that the latest version requires Microsoft Silverlight to be installed as well).  You can get the latest version of Windows Live Toolbar here.

If you’re not sure which, if any, of these components you have installed, click on the Tools menu (it should be under the search box at the top right of your browser window), hover over “Manage Add-ons” and then click on “Enable or Disable Add-ons”.  This will show you a list of the currently loaded add-ons in IE, and you should be able to identify one of the toolbars or the Windows Live Favorites extension in this list.

If you have trouble locating any of the components that have been discussed, please feel free to respond to this post either via a comment or to me directly (mweber@microsoft.com) and I’ll do my best to help you sort this problem out.