Improve company productivity with a Business Account.Sign Up

  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 2907
  • Last Modified:

OWA Already Exists when trying to install CAS role in exchange

Hi there,

I have had a problem with Exchange 2010 SP1 where I cannot install the client access role.  Due to a problem with IIS, it was removed and then reinstalled and this has now broken exchange in that I cannot get into EMS or EMC as it comes up with a WinRM error indicating that the URL could not be found.

I can run the exchange setup on the last page where it goes to set everything up it gets about 75% through the process on the Client Access Role and then comes up with the following:

Log Name:      Application
Source:        MSExchangeSetup
Date:          6/01/2014 2:32:59 PM
Event ID:      1002
Task Category: Microsoft Exchange Setup
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      {myservername}
Exchange Server component Client Access Role failed. 
Error: Error:
The following error was generated when "$error.Clear(); 
          $InternalOwaUrl="https://" + $RoleFqdnOrName + "/owa";
          new-OwaVirtualDirectory -DomainController $RoleDomainController -InternalUrl $InternalOwaUrl;
        " was run: "The virtual directory 'owa' already exists under '{myservername}/Default Web Site'.
Parameter name: VirtualDirectoryName".

The virtual directory 'owa' already exists under '{myservername}/Default Web Site'.
Parameter name: VirtualDirectoryName

Open in new window

I have checked IIS under the default website and there is no virtual directories under there at all.  Only the default documents iistart.htm etc.

Any help would be much appreciated.

4 Solutions
Gareth GudgerCommented:
Anything in the Application Pools?
open the IIS managger and under web service extensions check and make sure v2.0 is or allowed. Then try again to install CAS role.

If the issue continues, download the sp2 into local disk and install it again.
Launch adsiedit.msc on your domain controller, navigate to the following location:

Open adsiedit on your DC and go to below location.

CN=HTTP,CN=Protocols,CN=servername,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=ORG,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=DC,DC=com

Note: Replace the servername, ORG and DC with your exact names.

you will see an object for "owa" under HTTP at the above mentioned path.
Check the properties of this object and verify if it shows any references to old owa virtual directory. You can note down the properties of this object, delete this object and try reinstalling CAS again.
Creating Active Directory Users from a Text File

If your organization has a need to mass-create AD user accounts, watch this video to see how its done without the need for scripting or other unnecessary complexities.

chimp153Author Commented:
thanks for the replies.  I used ADSIEDIT and removed the owa, oab relating to the exchange server and started the install again.  This got me further, but now I have the following error coming up.

Summary: 3 item(s). 1 succeeded, 1 failed.
Elapsed time: 00:00:08

Preparing Setup

Elapsed Time: 00:00:00

Client Access Role

The following error was generated when "$error.Clear(); 
          $InternalOwaUrl="https://" + $RoleFqdnOrName + "/owa";
          new-OwaVirtualDirectory -DomainController $RoleDomainController -InternalUrl $InternalOwaUrl;
        " was run: "An error occurred while creating the IIS virtual directory 'IIS://myservername/W3SVC/1/ROOT/owa' on 'CCSBADM01'.".

An error occurred while creating the IIS virtual directory 'IIS://myservername/W3SVC/1/ROOT/owa' on 'CCSBADM01'.

ISAPI extension owaauth.dll in group MSExchangeClientAccess wasn't found and its status can't be changed. Please make sure this ISAPI extension (IIS Web service extension) is still listed in IIS Manager. If it's not, it may need to be added again.
Click here for help...

Elapsed Time: 00:00:07

Finalizing Setup

Open in new window

I have uninstalled/reinsalled the ISAPI Extension for IIS but still i get the same error appear.  

chimp153Author Commented:
diggisaur, I have three entries in Application Pools in IIS as below:

Classic .NET Appool     Started  V2.0  Classic  ApplicationPoolIdentity  0
DefaultAppPool           Started  V2.0 Integrated ApplicationPoolIdentity 1
MSExchangeOWACalendarAppPool Started v2.0 Integrated LocalSystem 0

Open in new window

chimp153Author Commented:

ASP.NET v2.0.50727 is allowed for both Framework64 and Framework and i have registered the dlls with IIS using the aspnet_regiis -i command.
Any progress?
chimp153Author Commented:
It looks like I might have fixed the problem.  I can now get into EMS and EMC.

First I had to run powershell in windows with admin rights and then do the following:

add-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010
New-Powershellvirtualdirectory -Name Powershell

This allowed me to create the virtual directory and from there I ran the troubleshooter called EMTShooter.ps1 from

So I am about to recreate the virtual directories now and see how I go..
chimp153 : Great going. Pls keep us updated about the progress.
chimp153Author Commented:
So everything is working again except for POP3.   We only have one client that uses POP3, the rest use RPC over HTTP so I am going to move that client over to the same.  

When I telnet into the Server on port 110 and enter the username and password I get an error 21 about the server being unavailable.  When I run the Test-PopConnectivity command in EMC I get an error that it couldn't find the Microsoft.Exchange.Compliance assembly.  I followed the instructions from here but now the POP3 service doesn't start at all when I add the  assembly in the Microsoft.Exchange.Compliance.exe.config file.

As I will not be using this and this is a different problem from the original post I am going to mark this as done.
chimp153Author Commented:
Thank you everyone for your help.
Glad the issue is fixed.
chimp153Author Commented:
thanks vSolution for your ongoing support.  I work in the I.T Department at a school and I may work on exchange once every couple of years so when something goes wrong I sort of have to relearn it a bit as it just seems to hum along most the time so it was good to have someone keeping in touch as I was trying to get it working.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Has Powershell sent you back into the Stone Age?

If managing Active Directory using Windows Powershell® is making you feel like you stepped back in time, you are not alone.  For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now