Outlook Web Access Blank After Installing SUS SP1 on Same Server as Exchange 2000

We had an extra server for managing the updates, but with SUS SP1 I installed it on our Domain Controller where Exchange 2000 is also running. The installation worked great. No lockdown was installed because I used it before.

But the problem is that Outlook Web Access doesn’t show emails anymore - the screen loads but no mail appears and it’s the same with the Public Folders.

I changed the Group Policy to point to the new server and installed a new Windows 2000 machine but no updates are installed.

I downloaded all updates and approved them. There was an error on the first sync something to do with xml but after changing the proxy login the sync worked fine!

Do I have to run the new version of lockdown or would that cause me more problems?

From the microsoft.public.softwareupdatesvcs newsgroup
You mention that URLScan was installed prior to installing SUS. In that situation SUS setup doesn't modify URLScan at all, so if EXEs were blocked prior to installing SUS they would have remained blocked - and the SUS server wouldn't have worked.

The problem with OWA not showing any updates could be the fact that parent paths/session state are disabled during SUS install. Try enabling the parent path / session state for the OWA application. From IIS Manager select the OWA application | Properties | Directory | Application Settings (Configuration) | Options. Check "Enable Session State" and "Enable Parent Path".