Hi,

Which OS X installed on your Mac?

I it is El Capitan (10.11), than AutoCAD 2013 for Mac is not supported on it.

If you have OS X Yosemite or Mavericks, than be sure to reinstall AutoCAD with this installer:

http://knowledge.autodesk.com/support/autocad-for-mac/downloads/caas/downloads/content/autocad-2013-...

During removing AutoCAD don't forget to un-check "Leave my preferences".

If this doesn't help, you may try to look here:

http://forums.autodesk.com/t5/autocad-for-mac-general/autocad-lt-2013-app-store-download-no-menu-bar...

and here:

http://upandready.typepad.com/up_and_ready/2013/02/autocad-lt-2013-for-the-mac-missing-menu-and-tool...

Maxim