Many of us had the same issue last year with Yosemite. It took over 4 months until Autodesk issued a patch (actually a version) that worked, and for quite a while it was not clear if they would so at all. I'll stay with Yosemite until this is clear this time. If they do not issue a patch or a SP, I will likely change to a free option like Draftsight. I've been using Draftsight last year during the time when AutoCad LT 2013 was OoO, and its OK as an alternative - and its free