Hi

Some Outlook 2013 Client cant pick up data in the roomfinder.

What to do :)  

HI 

Have you updated the OAB? 
Have you tried Outlook in Online mode?
Have you checked this is OWA ?
Run Test Email Autoconfiguration from the affected outlook and see the results

Check if the OAB is generation is successful by running the below command

Get-OfflineAddressBook | FL Identity,Server 

Also check your OAB VD by running the below command

Hi,

Please confirm whether other users can use the room finder in Outlook properly, such as Outlook 2010. In OWA 2013, please confirm if the Room lists are visible for select.

If the Room List can work well in OWA, it indicates the Room List distribution group which are used for Outlook Room Finder is created correctly in Exchange side. Then check the Room Finder feature in Outlook Online mode to narrow down the issue to OAB issue or client issue. In Exchange 2013, please restart the Microsoft Exchange Mailbox Assistants service to force generate the OAB.

If OWA works well and the issue only happens in Outlook Cached mode for some users not all users, we can do the following steps in Outlook to download Offline Address Book to check whether the issue persists:
1. Delete the *.oab files in the following folders in local machine:
     \Users\<username>\AppData\Local\Microsoft\Outlook\Offline Address Books
2. Create a new Outlook profile that uses Cached Exchange Mode.
3. Start Outlook 2013 with this new profile.
4. In the ribbon click Send / Receive, click Send/Receive Groups and then click Download Address Book.

Then check whether the issue persists.

Regards,