Greetings, We have an unusual situation where OAB distribution is set up correctly, its just that occasionally we get reports that information that should be in there isn't. For example a new employee was added to our email system at ~noon yesterday, and the OAB is generated 3 times a day (5AM, 2PM, and 9PM), so the user should have been added no later than late last night. I checked the Application log of the OAB generation server (we have the diagnostics logging on the OAL Generator set to Medium to record errors) and do not see this new user as an error condition. I got reports this morning that the user wasn't in the GAL, even after our users performed a deliberate download of the OAB through Send/Receive in Outlook. I checked the OAB folder on the CAS servers, and they had all updated content from 6 or 7AM today, so there should have been no reason why the 2PM or even 9PM update didn't have the user. I confirmed that the CAS servers were set to poll the file distribution point ever 240 mintues (4 hours) so there is no reason why the OAB shouldn't have had this user in it by 1AM our time (9PM + 4 hour offset). When I tried to download the OAB in my Outlook 2007 client, Outlook just hung never completeing the task. I had this issue once before and ran through a battery of tweaks to try and get it working, and one of those was running the Update-FileDistributionService against all of our CASs. So I performed that single step this time of running Update-FileDistributionService against our CASs, and within minutes the user showed up in the cache mode OAB. Just to summarize our system is Exchange 2007 SP3 RU3v2 (going to get v3 applied shortly), the OAB generation occurs 3 times a day (5AM, 2PM, and 9PM), is configured for web and public folder distribution, the web distribution has all of our CASs as distribution points, and all CASs are configured to check in every 4 hours. The files in the OAB folder on all of the CASs had files in it from 6 or 7AM this morning, but the user still wasn't showing up in the OAB. Does anyone know why running Update-FileDistributionService seems to have resolved our issue, and presumably once before, when it shouldn't be necessary to run it given the 4 hour check in on the CASs?

Just like you checked on the OAB folders on the CAS servers, did you check in the OAB folders on the Mailbox servers? It sometimes happens that there is a connectivity/ replication delays between the CAS and Mailbox servers because of which the OAB is generated on the CAS server but is not transmitted on the Mailbox server. Running the Update command helps to force replication between the two. You can also try to restart the File distribution service.

@Exchange_admin4help - I think you have it backwards. A Mailbox Server is the one that generates the OAB, and subsequently determines what versions of clients are supported and what distribution methods are chosen. When you choose the web distribution method, the mailbox server drops the OAB files into a share that the File Distribution Service on the CASs is configured to check periodically (in my case every 4 hours). It is my understanding that if the files were updated on the CASs OAB folder (which is mapped as a virtual directory called /OAB off of the web server aspect of the CAS), they were done so only because the CAS File Distribution Service noticed an update in the generating mailbox server's OAB share. If you believe I am in error, please clarify what I have wrong.

HotFix is right. The OAB file is generated on Mailbox server and then replicated to the CAS server. The update time is based on the Polling Interval time. The default setting is eight hours (480 minutes). First, I would like to confirm how many CAS servers there are. Please access the following cmdlet to assure the Polling Interval time is set correctly on all CAS servers. Set-OABVirtualDirectory "OAB (Default Web Site)" –PollInterval 240 Then, please reproduce the symptom to check the result. If the issue persists, please restart the File Distribution Service. Meanwhile, please verify whether there is any OAB error message in Event Log. If so, please post it here. Thanks. Novak Wu TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

@Novak: There are 3 CAS servers in this enviornment. I confirmed the prior to doing anything that the OAB Poll Interval was 240. I'm not sure how I can reproduce the problem as I am not sure how/when it creeps in until someone notices the OAB just isn't updating. As for restarting the file distribution service, isn't that essentially going to produce the same result as running the Update-FileDistributionService command? We know that fixes it now having been through this scenario twice, but the question is why is that needed. As for OAB errors, we do have some contacts that have malformed aliases and are therefore skipped in the OAB generation process. This is common in enviornments with older MIIS sync products, and we are working to resolve that situation, but they shouldn't be causing the CASs to not download and properly distribute the latest OAB. Otherwise we don't have any errors on the OAB generation server that i am aware of. I am not sure if you meant look for OAB errors beyond the generation server though. The only errors I see on the CASs is the following which I will look into, but I don't think has anything to do with the OAB distribution: Log Name: Application Source: MSExchange Common Date: 4/11/2011 10:05:03 PM Event ID: 4999 Task Category: General Level: Error Keywords: Classic User: N/A Computer: EXCHCAS1.company.com Description: Watson report about to be sent to dw20.exe for process id: 11916, with parameters: E12, c-RTL-AMD64, 08.03.0083.006, MonitoringHost, M.E.D.Storage, M.E.D.S.ConnectionCachePool.SetConnectionCacheSize, M.E.D.Storage.StoragePermanentException, fb5c, 08.03.0137.000. ErrorReportingEnabled: True

Have you created a CAS array in the environment? Meanwhile, I would like to confirm whether the new added user list on the GAL after longer time without running the Update-FileDistributionService command. I mean that you can create a test user mailbox and generate a new OAB, then publish to CAS server again. Please verify the detail modified on each Mailbox server and CAS server. 1. Access the following location and check whether the OAB file is latest. Please verify the time under the “Date Modified” tab. The OAB file is usually generated every day. C:\Program files\Microsoft\Exchange Server\ExchangeOAB\<some GUID> 2. Access the following location and check whether the latest OAB file is published successfully. Please verify the time under the “Date Modified” tab. Please compare the time on CAS server to the generated OAB file on Mailbox server. C:\Program Files\Microsoft\Exchange Server\ClientAccess\OAB\<some GUID> Regarding to the event ID 4999, I agree with you that it’s not related to OAB distribution. Thanks. Novak Wu TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

How is thing going on? If there is any question, please feel free to post it here. Thanks. Novak Wu TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

I don't have a CAS Array in the enviornment because this is Exchange 2007. I do have a hardware load balanced VIP that points to 3 CASs who all participate in the file distribution. Currently I am waiting for the problem to re-occur. I.E. Something not showing up in the OAB that should be there. I have been checking almost daily, and just like the first time this happened the problem hasn't immediately returned. I used the exact same steps #1 and #2 to provide the information in the original post, so I am not sure why the OAB wasn't downloading. I.E. The files in both locations were less than 12 hours old, and the object was created the business day before. Since no one else has posted that they have seen this behavior, I suspect I will have to open a ticket with Microsoft if/when this issue re-occurs.

OK. If there is any update, please feel free to post it here. Regards, Novak Wu TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.