I recently had trouble upgrading from 07.03.04 to 07.04.00 but figured it out. I had a couple of sites that had custom registration forms and hidden was the field called "Use Email Address as Username". It was checked and causing a problem when upgrading. So, I unchecked the box and my upgrade worked just fine. I was also able to upgrade to 07.04.01 without incident.

But the problem still exists. If I go into any site settings and check the box to "Use Email Address as Username" field and try logging in using my HOST account on that site, I lose the ability to use my HOST account on any site. It keeps telling me my password is incorrect. When I try and reset it, nothing I enter is accepted. Anyone else have this problem?