For the first question, I am suspecting the Default Offline Address List has not been created successfully. This is because folders of OAB Version 2, OAB Version 3a and OAB Version 4 will be created by OABgen the first time a Offline Address List is created. Since the Default Offline Address List is not being used, we may ignore this issue. Refer to: http://blogs.msdn.com/b/dgoldman/archive/2006/08/10/how-to-deal-with-multiple-oab-public-system-folders-of-the-same-type.aspx Regarding the BPA error, generally it provide a link of resolution/explanation for the error it reports. Could you provide the exact error message? thanks. Fiona Liao TechNet Community Support

Hi Thanks for replying. The actual error from BPA is: "Offline address book replica not found Organization: Company Name Didn't find a replica of folder 'OAB Version 2' for offline address book 'Default Offline Address List'. Either a replica doesn't exist, or this folder hasn't been created yet. If an OAB generation attempt has not yet been made, you can ignore this error." It gives the same error for OAB Version 3a and OAB Version 4. I would assume it's safe to ignore the error as this is NOT set as the default address list ? But I was just curious why the 3 OAB's were not listed for the address list. Are the OABs only generated when a client actually requests a download and, if clients aren't using this one, this will never have been done ? Would like to resolve the issue (if there is one) in cas we want to start using this address list in future. Thanks

Yes, we may ignore this error. The OAB file is generated regularly at every 4:00am, regardless if it is used or not. You may delete the "Default Offline Address List" and then create a new offline address list with the same name. After that, click "Update" in ESM to force generation immediately (You might need to restart mailbox assistant service and wait for some minutes). Fiona Liao TechNet Community Support

Hi We have a mixed Exchange 2003 / 2010 environment - ongoing migration project. The Default Offline Address List is NOT actually set as the default at the moment as there is another address list being used as the default. Address lists are still being generated on the EX2003 server. I'm curious as to why the Default Offline Address List has no details listed (folder names) when viewed in the Exchange System Manager. The other address lists have OAB Version 2, OAB Version 3a and OAB Version 4 listed on the Details tab. Also - the BPA is throwing up errors regarding there being no replicas for the 3 versions of OAB mentioned above. Can anyone advise ? Thanks John

Hi Thanks again for your respone. Regards John

Hi Sorry - just to confirm. We're definitely OK to delete the "Default Address List" and recreate with the same name ? There's no risk of this "breaking" something ? Thanks John

Hi, you can recreate the default address list without deleting old one. Find the below article for reference; Exchange 2010: http://technet.microsoft.com/en-us/library/bb124339.aspx Exchange 2003: http://www.msexchange.org/tutorials/offline-address-book-best-practice.html Regards, Ajaj Desai (India)MCP,MCTS

For the first question, I am suspecting the Default Offline Address List has not been created successfully. This is because folders of OAB Version 2, OAB Version 3a and OAB Version 4 will be created by OABgen the first time a Offline Address List is created. Since the Default Offline Address List is not being used, we may ignore this issue. Refer to: http://blogs.msdn.com/b/dgoldman/archive/2006/08/10/how-to-deal-with-multiple-oab-public-system-folders-of-the-same-type.aspx Regarding the BPA error, generally it provide a link of resolution/explanation for the error it reports. Could you provide the exact error message? thanks. Fiona Liao TechNet Community Support