I ran some Windows updates on a Microsoft OCS 2007(Office Communications server) server running on 64bit Windows 2003, and when I rebooted, the front-end service would not start.
I realised that having just run some updates, that one of them would be the culprit.
So I had a look around and found that I need to remove the KB974571update, reboot and then the service started prefectly!
If you have users who’s computers are not domain members, but want to be able to use the Office Communications 2007 client software, then you need to change the username string so that they can connect. The users must have a valid domain account and OCS account to be able to use the software.
After installing the client, enter the OCS email address and when it asks for the username, use the entire FQDN for the domain, not just a single word.
For example, if you domain is company.com and the username is user, don’t use companyuser , use company.comuser as the login.
You should then be able to authenticate and use the software.