When connecting to Outlook Web App (OWA) for Exchange Server 2010 users may report the following error in their web browser.
Outlook Web App didn’t initialize. If the problem continues, please contact your helpdesk.
Couldn’t find a base theme (folder name=base)
This can be caused by missing OWA theme files in \ClientAccess\Owa\14.1.287.0\themes sub-folder of the Exchange 2010 installation path. By default this is C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\14.1.287.0\themes.
If that is not available to you then you can also restore the files by re-running Exchange Server 2010 SP1 setup in upgrade mode.
C:\Admin\Exchange2010SP1>setup /m:upgrade Welcome to Microsoft Exchange Server 2010 Unattended Setup Preparing Exchange Setup Copying Setup Files COMPLETED The following server roles will be upgraded Languages Hub Transport Role Client Access Role Management Tools Performing Microsoft Exchange Server Prerequisite Check Configuring Prerequisites COMPLETED Language Pack Checks COMPLETED Hub Transport Role Checks COMPLETED Client Access Role Checks COMPLETED Configuring Microsoft Exchange Server Language Files COMPLETED Restoring Services COMPLETED Languages COMPLETED Hub Transport Server Role COMPLETED Client Access Server Role COMPLETED Exchange Management Tools COMPLETED Finalizing Setup COMPLETED The Microsoft Exchange Server setup operation completed successfully.
You should now see the restored files in the correct location, and OWA will begin working again.