Here's an error I've seen when adding while decommissioning a different node.
INFO [GossipStage:1] 2014-08-06 00:37:43,615 StorageService.java (line 1614) Removing tokens [-1092160356339948581, -1135452450397885068, ... ERROR [GossipStage:1] 2014-08-06 00:37:43,618 CassandraDaemon.java (line 194) Exception in thread Thread[GossipStage:1,5,main] java.lang.NullPointerException at org.apache.cassandra.utils.UUIDGen.decompose(UUIDGen.java:82) at org.apache.cassandra.db.HintedHandOffManager.deleteHintsForEndpoint(HintedHandOffManager.java:166) at org.apache.cassandra.service.StorageService.excise(StorageService.java:1615) at org.apache.cassandra.service.StorageService.excise(StorageService.java:1630) at org.apache.cassandra.service.StorageService.handleStateLeft(StorageService.java:1515) at org.apache.cassandra.service.StorageService.onChange(StorageService.java:1234) at org.apache.cassandra.gms.Gossiper.doNotifications(Gossiper.java:953) at org.apache.cassandra.gms.Gossiper.applyNewStates(Gossiper.java:944) at org.apache.cassandra.gms.Gossiper.applyStateLocally(Gossiper.java:902) at org.apache.cassandra.gms.GossipDigestAckVerbHandler.doVerb(GossipDigestAckVerbHandler.java:57) at org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:56) I didn't see anything in JIRA about the same issue, but there are similar issues. Has this been fixed? Is this a new bug? This is Cassandra 1.2.9. Thank you.