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OWA won't load after applying Exchange 2007 SP1 security patch

Microsoft's security patch, Update Rollup 2 for Exchange Server 2007 SP1, can break the Client Access server. When this occurs, logging into Outlook Web Access (OWA) returns a blank screen. Find out how to fix this OWA issue and also how to avoid future patching problems.

Microsoft's security patch, Update Rollup 2 for Exchange Server 2007 SP1, can break the Client Access server. When this occurs, logging into Outlook Web Access (OWA) returns a blank screen. Find out how to fix this OWA issue and how to avoid future patching problems.

One of the cardinal rules of the patch management process is to test patches before deploying them to production servers. I have to confess that recently I applied patches to the Exchange 2007 servers on my network without testing them first. In the process, I ended up breaking the Client Access server. There is a silver lining to this story though; I was able to determine which patch caused the problem.

Why did I apply Microsoft security patches without testing them first?

  • There are only two users on my network. If something goes wrong, I have to fix the problem myself. However, I don't have to deal with the consequences that would exist if I made the same kind of mistake in a corporate environment.

  • I am in the middle of writing a book on patch management. Because I knew that I would need screen captures for the book, I stopped patching a few weeks before I began writing. By doing so, I would have plenty of unapplied patches to work with as I wrote the book.

After writing about a third of the book, I knew that I needed to bring my network up to date. Because I was backlogged in the patching department, I decided to apply all of the latest patches.

More on Exchange security and patch management:
Proper patching for front-end/back-end Exchange Server setups

Enable automatic Exchange IMF updates via Microsoft Update

Deploying WSUS for Exchange patch management

Ask an Exchange Server security question

The next day, I needed to log into Outlook Web Access. When I tried to access my OWA website, which is only accessible from inside of my network perimeter, I received a blank screen. At the bottom of the browser window, Internet Explorer (IE) displayed: Completed, but with errors.

I then tried to log into OWA from other computers, reboot the server, verify that all of the Exchange services were running, etc. It became clear that one of the Microsoft security patches caused problems on the Client Access server.

Unfortunately, I had applied so many patches that I had no idea which one had caused the problem. My only option was to take a closer look at the Client Access server to see if anything looked out of the ordinary.

I discovered that the Client Access server previously stored OWA template files, scripts and CAB files in a folder named: \Program Files \Microsoft \Exchange Server \ClientAccess \Owa \ During the patch, a new folder was created named: \Program Files \Microsoft \Exchange Server \ClientAccess \Owa \ All of that folder's subfolders were empty. I now had enough information to research the problem further on the Internet.

Apparently, Update Rollup 4 for Exchange Server 2007 has a known bug. In some circumstances, the patch disables Exchange services. The services could be manually re-enabled, but doing so won't fix the OWA problem because the patch instructs OWA to use an empty subdirectory for its source files.

The patch did not disable any of my Exchange services, but the symptoms seemed similar enough that I decided to do some more research. I didn't apply Update Rollup 4; however, I applied a newer patch -- Update Rollup 2 for Exchange 2007 SP1 (Update Rollup 4 was a pre-SP1 update).

Update Rollup 2 for Exchange 2007 SP1 fixed the problem that caused the patch to disable Exchange services, but the OWA problem persisted. To get around the problem, I made sure that all workstations were logged out, and that no mailboxes were open. I then manually downloaded and applied Update Rollup 2 for Exchange 2007 SP1. Once installation was complete, I restarted the Exchange services and the problem was fixed.

About the author: Brien M. Posey, MCSE, has previously received Microsoft's MVP award for Exchange Server, Windows Server and Internet Information Server (IIS). Brien has served as CIO for a nationwide chain of hospitals and was once responsible for the Department of Information Management at Fort Knox. As a freelance technical writer, Brien has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal website at

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