Biztalk and .NET 4.0

We recently discovered that Enterprise SSO service fails to start if you install .NET 4.0 Beta bits.  This causes a downstream failure on Biztalk services failing to start as the dependant ESSO fails.  We are still investigating the possible fix and I will update this post once we have a resolution.  Please do no install .NET 4.0 on existing Biztalk installations.  The issue applies to all versions of Biztalk and SSO.