If a user has ever attempted to run IE7 Beta1 in an unsupported side-by-side configuration with a version of IE6, IE7 Beta1 puts a registry key on the machine the first time a user executes the IE7 version of IEXPLORE.EXE. This key is part of an normal IE7 installation on XP, and will not be configured correctly if an unsupported side-by-side install is used. When IE7 is installed using the installer, the key should be removed properly upon uninstall. A machine can also load this registry key and not remove it during a failed IE7 installation.

To address this issue on a machine running IE 6 SP1 with our most recent security update, locate and delete this entire key from the registry of the affected machine:

HKEY_CLASSES_ROOTCLSID{c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6}.

If you are running IE7 Beta1 in a side-by-side scenario with another version of IE, this is not a supported scenario. Please uninstall and reinstall IE7 Beta1 in the recommended manner.