I am unable to failover the mailbox databases, this worked earlier today, I updated/patched the server the databases moved off. When I tried to move them back so I could update the other server I got failures saying the copy queue length was 9223372036853891591.

I have tried following the instructions given here (for Exchange 2010 I know, but same error) http://blogs.technet.com/b/timmcmic/archive/2012/05/30/exchange-2010-the-mystery-of-the-9223372036854775766-copy-queue.aspx and it tells me it succeeded but the logs lost is zero. The databases will not mount and both copies say they are passive yet mail still flows.

Any suggestions?

Please run 

Get-MailboxDatabaseCopyStatus | fl and post it over here for better answers 

Hi,

Please try to Deleted the keys DatabaseGUID  and DatabaseGUID_TIME  under HKLM\Cluster\ExchangeActiveManager\LastLog

• DatabaseGUID with a decimal value representing the last log generated by the active copy
• DatabaseGUID_TIME with the system time of when that log file was generated

Then restart the replication service.

After that, check the Copy Queue Length and Failover Cluster manager.

Best Regards.

Does moving the cluster group from node to node unblock things?

I was unable to move anything until I started to reseed one database, then within seconds all CQLs dropped to zero and all but the database being reseeded were able to move. The reseed took 9 hours to complete, but once complete it was able to move and everything went back to normal.

I have no idea what caused this issue, but a resolution was found

• Marked as answer by GADavies 17 hours 22 minutes ago