After upgrading SharePoint Server to SP1 or later, you are no longer able to view Word or PowerPoint documents with Office Web Apps Server 2013.
Office Web Apps give the error of "Sorry, we ran into a problem." and gives the options to Restart, or Exit.
Software combination scenarios we see the issue:
Internet Explorer, Office Web Apps Pre SP1 and SharePoint SP1 or greater
Update Office Web Apps Server to at least SP1 (http://support.microsoft.com/kb/2880558)
*Note you must follow the process below to apply updates to Office Web Apps 2013
Even after upgrading SharePoint 2013 to SP1 and Office Web Apps Server to SP1, the issue still remains when viewing Word documents using Word Web App.
If you are getting the same error screen as above, I would recommend to rebuild the farm now that Office Web Apps is at SP1. If you are still having issues, I would suggest to open a support case to troubleshoot further.
I have applied OWA SP1, but I still get the error message with PDFs only. Any ideas