You Cannot open OWA Interface after applying Exchange 2010 SP1 #Microsoft #Exchange2010

Consider the following scenario:

you have Exchange 2010 RTM infrastructure up and running, you applied SP1 to the servers, after applying Exchange 2010 SP1 you lost access to the OWA Virtual Directory, when accessing the OWA virtual directory you might get:

Error1:

Internet Explorer cannot display this page

Error2:

Could not load file or assembly ‘Microsoft.Exchange.Diagnostics, Version=14.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35’ or one of its dependencies. The system cannot find the file specified.

Error3:

when opening the OWA virtual director application path you get “invalid application path”

Cause:

there are several root causes of this issues, below are my findings for the cause of these errors:

Cause1:

you are using wrong redirection configuration to redirect http to https traffic, the correct way to configure Exchange 2010 to redirect http to https traffic could be found here

http://briandesmond.com/blog/redirecting-owa-urls-in-exchange–2010/

using other techniques will lead to OWA loading errors.

Cause2:

Wrong configuration in the OWA web.config application, to correctly load it rename the file to web.config.old and restart iis.

Cause3:

in-complete SP1 or RU installation, try to remove SP1/RU and install it again.

Cause4:

I found the above issue on servers that had IE9 installed, didn’t have the chance to test whether uninstalling IE9 fixed the issue or not, as un-installing IE9 was taken among other steps to fix the issue, but if you might want to take a look to IE9.