Not sure why, but the past two full backups (NT backups) have terminated unexpectedly with 1159 errors (IS Events). As a result the log files are growing in number. Before this problem, I planned to do an offliine defrag of the priv and pub edb files (I still plan to do it this weekend). My question is: after dismounting the store (mailbox and public) can I safely move off to a NAS device the surplus log files (I understand I should identify the 'Log(s) Required' (KB240145) that should be kept)? I have enough space to keep them on the server's disk drive. Does it matter if they are left where they are during the defrag? After completing the defrag and mounting the store I will be doing (or trying to) a full backup. Again, should those log files be there, will the backup delete them if successful, or does the defrag break that dependency and so they are no longer needed?