Devise, IE8 and Authentication prompt

I've been using Devise in an app for a while and it all works fine for me in all browsers (Safari, Firefox, IE6, 7, 8 etc)

I have a new user who has a开发者_JAVA技巧 fairly locked down version of IE8 and as soon as they try to access the app, before they even get to the login page, they get a Windows Authentication prompt appear. If they try to enter the login details they have been provided it fails. I'm not really worried about it failing, as the authentication prompt shouldn't be appearing.

I've tried suggesting allowing cookies etc, but they are still getting the problem. Has anyone got any suggestions as to other things we could look at?

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It appears the upgrading to Rails 3.0.5 and Devise 1.2 resolves this problem