Have you tried truncating (emptying) your sessions and cache tables in the database?
I tried that--I tried everything. Eventually I had to roll back the upgrade. I discovered that the original was a few releases behind current for 4.6, so I upgraded it to the last 4.6 release and then I'll have a bash at 4.7 later this week. I'm officially spent at present. :)
Lynn S.
------ Mama, homeschooler, writer, activist, spinner & knitter http://www.siprelle.com
NOTICE: The National Security Agency may have read this email without warning, warrant, or notice.