Microsoft Exchange stopped working after uninstalling or removing WSUS Role

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ISSUE

When we uninstall Windows Server Update Services (WSUS) from the server where Microsoft Exchange is also hosted then we start getting HTTP 500.19 errors in OWA and ECP.

CAUSE

The uninstall of WSUS also effects IIS. The reason for this is that when we add WSUS role to the server it installs a dynamic compression module and adds XPress compression scheme for WSUS site at the global level in IIS. This modules loads this compression scheme in all application pools for each website in IIS accessed by clients.

Now when we uninstall WSUS role from the server. It uninstalls everything but leaves the following which we have to remove manually afterwards.

1. Remove “WSUS Administration” website in IIS.
2. Remove Wsus pool in IIS
3. Remove Xpress compression scheme from IIS applicationhost.config file

Microsoft Exchange heavily relies on IIS for OWA, ECP, Autodiscover etc. So when it tries to load these exchange sites, all of them start producing errors due the XPress compression scheme defined in %WINDIR%\system32\inetsrv\config\applicationhost.config which has a reference to C:\Program Files\Update Services\WebServices\suscomp.dll file and IIS is trying to load this file and it cannot find and hence results in HTTP 500.19 errors.

Solution

We can sort this out using the following two fixes.

Fix 1

Step 1 Go to the actual physical file located on the server at the following location.

%WINDIR%\system32\inetsrv\config\applicationhost.config

Step 2 Open this file in Notepad, and find <schema name=”xpress” which should be under <httpCompression>

Step 3 Remove the above highlighted line.

Step 4 Save the file and close.

Step 5 Once saved then, restart IIS and it should load the sites now correctly.

Fix 2

Step 1 Open command prompt as an Administrator.

Step 2 Run the following command to remove this from the configuration file.

%WINDIR%\system32\inetsrv\config\applicationhost.config

Step 3 Restart IIS using the following command

iisreset

Once done, the sites should work.