Hi

We have Exchange Server 2010 deployed in our enterprise. 

For the last few days our GAL is not getting updated. On checking the server I found out that our OAB generation is corrupeted. Following is the message:

OABGen detected that the file "" is corrupted or missing.

As I understand I will need to rebuild the OAB again.

However I wanted to know why did the OAB suddenly become corrupted.  How do I identify the reason for OAB getting corrupted suddenly?

Basically I do not want to rebuild a GAL and know that all of a sudden one day it got corrupted .

Any kind of suggestions/help would be greatly appreciated.

Hello,

Following can be the reasons as per my understanding:I also suggest you checking event logs around the oabcorruption entries

-Virus scanning the OABVirtual Directory on the Exchange Server

-Disk problems. Some of the disk sectors that are containing the OAB files become corrupted

-Permissions problems on the OAB directory have changed

-Replication issues between various Exchange servers

Addition to what ManU said, have seen this when C: drive doesn't have enough space and fails (this might not corrupt the OAB but might be coincident in my case) specially it keeps the files in c:\windows\temp folder temporarily during generation...

Hi,

For your reference, the following article descripted detailed information about the reason and solution for OAB Generation logs of Event ID 9373 (It is also applied to Exchange 2010 OAB):

http://blogs.msdn.com/b/dgoldman/archive/2008/12/16/oab-generation-logs-an-event-id-9373-when-you-update-the-offline-address-book-in-exchange-server-2007.aspx

Regards,