This sounds kinda similar to what happened to us after upgrading from 10.1.0.3 to 10.1.0.5. From my posting in 2006 about our Upgrade-from-Hell " //www.freelists.org/post/oracle-l/Upgrade-from-92-to-102-NONRac-Basic-Steps,2 ": *[Oracle Support] was able to identify the cause of the problem in the VIP trace file. It was occasionally timing out while checking the default gateway. The timeout threshold was 2 seconds and the engineer had us change that to 10. * Perhaps this will help. -Mark