Slow OWA Performance

Issue: when you try to use OWA to connect to the SBS 2003 Server from the Internet, you will experience very poor performance. 

Note: these instructionsw ere provided by Frank Chen [MSFT]:

If the issue occurs with premium option selected when you connect to the OWA externally, let us disable “Enable Forms Based Authentication for Outlook Web Access” option, please follow these steps:

1. Click “Start”, point to “Programs”, point to “Microsoft Exchange”, and then click “System Manager”.
2. Expand “Servers”, expand “<ServerName>”, expand “Protocols”, and then expand “HTTP”.
3. Right-click “Exchange Virtual Server”, and then click “Properties”.
4. Click the “Settings” tab.
5. Click to clear the “Enable Forms Based Authentication for Outlook Web Access” check box.
6. Click “OK”.
7. Restart the following services:
– Microsoft Exchange System Attendant service
– IIS Admin Service

If the issue still remains, please follow these steps:

At the SBS 2003 server:
1. Clear the IIS server files follow these steps:
    a. Go to the %windows%\IIS Temporary Compressed Files directory
    b. Select all of the content in this directory and delete it.
2. Go to a command prompt, type “iisreset”.

At the external client:
1. Please open IE and click Tools -> Internet Options
2. Select Delete Files and click OK to confirm that you want to delete the

Frank Chen, MCSE
Microsoft Partner Support Professional

4 thoughts on “Slow OWA Performance

  1. I have found a way to speed up my login for my OWA page by doing the following:

    Going into properties of the exchange directory in IIS (i.e. IIS/Web Sites/Default website/Exchange)

    Click on the Directory Security tab, then click on Edit in the Authenication and access control. In here I cleared out the Default Domain and Realm boxes at the bottom, and now it’s 20 times faster to get logged in. In my situation, the only box I have checked in the Authenticated access section is, "Basic authentication." All others are left unchecked.

  2. Can a large inbox size has anything to do with it. I have a user that has sub folders under inbox and saved most of his stuffs there. The total size of his inbox + subfolders is 2.6 GB!

    I am trying to find any article regarding this that might affect OWA. Anyone know where I can find such info?



  3. If there is a large amount of messages in the inbox, yes it will slow it down dramatically. It is always better to put messages in sub folders, but nonetheless, 2.6 GB is HUGE!!! I would suggest to archive those messages somewhere as a backup. Save the attachments somewhere on the local machine or network drive and delete an e-mails that aren’t used. I am guilty of not throwing away things too, but "tidy up the mailbox."


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