have you tried powering everything off. Then start the mini then one of the computers and see what the access is like?

Yes. But thanks.

It's now a lot more complicated than that...

If anyone wants to get paid to visit and fix it, I'd love to hear from you.

I did tell you.. Its just not worth the hassle! Trust me.. i did this for years and i grew to hate OS X server!

Probably not what you want to hear but short of starting from scratch and rebuilding your server, which is what i ended up doing in most cases i can't really help.

I run a Mac OS X server in a enterprise environment. I seriously suggest scrap the idea of a Mac server for the above unless you plan on adding a lot of Macs to the point you need to use Active Directory/Open Directory to manage them I would say 30+!

Its a nice appealing idea not its really not practical for a few machines especially not with OS X server being the neglected useless 'addon' that it is now...

If the iMac isn't logging in use network accounts log in as the local user, un-bind and re-bind to the OS X server see if that allows you to log in, otherwise check Console.app for any errors/info. I'm assuming you've setup Open Directory to use network accounts?

Correct. Not what I wanted to hear!

I'm persisting.

Now on day 5 (it had been running fine for two weeks until I connected another computer to the network) of trying to fix it and a third reinstall if the OS & app.

This time I'm going for the absolute basics...