I am getting the following Warnings over and over. (Different users) Process Microsoft.Exchange.AddressBook.Service.exe (PID=2152). Recipient object CN=XXX,OU=XXX,OU=XXX,OU=XXX,DC=XXXX,DC=org read from <Domain Controller> failed validation. A partially valid object will be returned. Set event logging level for Validation category to Expert to get additional events about each failure. I have enabled Expert logging and it just seemed to increase the number of Warnings. I have run DCDiag against all of the DC's and all is healthty We have Exchange 2010 on 3 different servers with 4 DC's in the eviroment. We have a exchange 2003 server running public folders only.

Hi Robert, Please install the latest service pack and rollup for Exchange 2010 first: ADAccess validation errors http://social.technet.microsoft.com/Forums/en/exchange2010/thread/3d346295-86fe-4372-aada-42826c5994fe Frank Wang 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.

Hi Robert, Any updates?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.

We have this error as well- Event 2158 in Exchange 2010 SP1. After setting Validation logging to Expert, [In Exchange management Shell: set-eventloglevel -identity "MSExchange ADAccess\Validation" -Level "Expert"] we get Event 2161, MSExchange ADAccess Process Microsoft.Exchange.AddressBook.Service.exe (PID=2588). Object CN=ExchangeServices,OU=<OU>,OU=<OU>,DC=<Domain>,DC=com read from <ADSERVER.domain.com> failed validation. Attribute: ExchangeLegacyDN. Error message: You must provide a value for this property.. Invalid data: . I discovered this troubleshooting an issue where Outlook 2003 clients do not retrieve updates in the GAL and put them in the OAB. Frank

Sorry for delayed reply. SP1 did fix the issues for me.