Hi, Some how I deleted the default offline address book and created the new offline address book. But its not being generated and the required folder whihc is created by default by GUID name of the OAB is not created. When I see the details of OAB in exchange management Shell its shows the GUID also. Anyone there to help me on urgent basis. regards. rajesh

Hello, I understand that the problem is new Offline Address book (OAB) will not generated. You found that the GUID folder even not be created under the ExchangeOAB folder. Meanwhile, you can get the GUID by checking offline address book in the EMS. Anything incorrect, please let me know. Herein, I want to tell that the OAB update schedule time is running at 5:00AM daily by default. After creating an OAB, the GUID folder cant be created till the update time, when the time coming, System Attendant service should get GUID from AD and create this folder by the GUID name. By the way, you can update OAB manually which also will create this GUID folder immediately. To update OAB manually, please check steps, In EMC->..>Find the Offline Address book, Right click the OAB and select update button. Or you can run below cmdlet in EMS: Update-offlineaddressbook id OAB name. If the issue persists, please tell me know. event log will be more effective for troubleshooting. -Jason

Jason, in cluster configuration OALGen trying to put OAB to share ExchangeOAB on cluster node, instead of cluster resourcename where really presents this share (ExchangeOAB). For example Eventlog for MSExchangeSA on active node for Clustered Mailbox resource- OALGen detected that the file '\\CL-NODE-1\ExchangeOAB\93a1928b-5661-4f94-83ab-5f8e0729ea69\44f7a3c1-4de0-496b-b4a0-418b6a6e9620-data-1.lzx' is corrupted or missing. This indicates data tampering or disk problems. Restore files in this folder from the recent backup or clean up folder content and force a full OAB generation. - Default Offline Address Book C:\>net view \\CL-NODE-1Shared resources at \\CL-NODE-1 Share name Type Used as Comment -------------------------------------------------------------------------------Address Disk "Access to address objects"The command completed successfully. C:\>net view \\CL-MAILBOXShared resources at \\CL-MAILBOX Share name Type Used as Comment -------------------------------------------------------------------------------ExchangeOAB Disk OAB Distribution shareThe command completed successfully.