How did you do the upgrade? Did you use the upgrade package or the install package? If would seem that you may have overwritten the machinekey setting in web.config.
Did you make a complete backup of your site? If you did, I would recommend that you restore and try the upgrade again. To be on the safe side, do the upgrade on a local site and then move it to production when it is successful.
Any details that you can provide will help. |