Unless youLre running an NI cluster. If PEDRIVER is loaded shutting the decnet circuit used by it must crash the node. I would have thought that shutting off decnet will not affect SCS traffic. If it happend that it did, AND there were two or more nodes in the cluster trying to communicate and failing, I would expect one or more nodes that lost quorum to hang for RECNXINTERVAL seconds (by default, 20). After that, one or modes might bugcheck with a CLUEXIT exception. A SSRVEXCEPT exception much more likely indicates something is wrong with the software. Regards, Peter Coghlan.