What is so frustrating about this is that Autodesk has no direct mechanism to communicate these problems directly to the people who can solve them.  We have to go through this round about forum method and JUST HOPE that someone at Autodesk is monitoring these forums and will do something about the problems we discuss that require Autodesk to solve the problem.

This problem could not have been avoided at least for me, as I had already upgraded to Yosemite and AutoCad LT was working fine.  It was not until I migrated to a new SSD that AutoCAD LT broke under yosemite. Now I cannot get Service pack 2 to install and therefore cannot install service pack 3.  Autodesk needs to provide a service pack 3 that includes all of service pack 1 and service pack 2 so people like us who had a working program under Yosemite can now get it back up and running.  It is not like 2013 will not run in Yosemite, there are just some problems that need attention.  Service pack 3 says it solves thos problems but without service pack 2 how can we possibly run service pack 3?????

We all need to keep prodding Autodesk to fix this in any way we can.  It has disrupted my business and is costing me money and possibly clients.