follows is the requirements by AutoDesk:

System Requirements
Apple® Mac® OS® X v10.10.0 or later (Yosemite)
Apple Mac Pro® 4,1 or later (Mac Pro® 5,1 or later recommended); MacBook® Pro 5,1 or later (MacBook Pro 10,1 with Retina Display or later recommended); iMac® 8.1 or later (iMac 11.1 or later recommended); Mac® mini 3.1 or later (Mac mini 4.1 or later recommended); MacBook Air® 2.1 or later; MacBook® 5.1 or later (MacBook 7.1 or later recommended)
3 GB of RAM (4 GB recommended)
2.5 GB free disk space for download and installation (3 GB recommended)
All graphics cards on supported hardware
1,280 x 800 display with true color (2880 x 1800 with Retina Display recommended)
All Mac OS X supported language operating systems
Apple® Mouse, Apple® Magic Mouse, Magic Trackpad, MacBook® Pro trackpad, or Microsoft-compliant mouse.
Mac OS X-compliant printer

have you tried uninstalling/reinstalling LT?