Before going crazy, just install 5.5 on it. It will probably be okay on a new machine provided you do not use migration assistant. Use the original installer or download it from here: https://helpx.adobe.com/creative-suite/kb/cs5-5-product-downloads.html
It's been installed from the Adobe website. Disk permissions repaired. Mac restarted. Java downloaded. CS5.5 opens but it spins when I try to open a CS5.5 document or create a new one. Thx for your help.
For right now, you could download the CC2014 trial to get this done.
At some point you’re not going to have a choice and I’m not enough of a Mac expert to direct you to virtual machines for earlier operating systems.
Did that to get the immediate problem solved but unfortunately for tomorrow's deadline saving in IDML format is unacceptable for my coworkers.... Calling the Apple store now.... Thx again.
Can I install a prior OS to get CS5.5 to work?
I have CS 5 running on an iMac with Yosemite. I assume you've tried disabling any third party plugins and scripts, and any non required fonts? Have you tried starting up in Safe mode? Also, there have been reports of browser extensions conflicting with ID, so trash any browser add ons.
Disk permissions repaired.
You could also try clearing caches and log files and running the OSX maintenance scripts via an app like Cocktail