Can't install update on Mac

Tried twice to install LO 4.3.4 on Mac OS X 10.8.2. Meets (exceeds) all system requirements. American English.

I am not a Mac expert but just installed on Mac OS X10.6.8 without any problem. I downloaded from:

It downloads but won’t install. The default app to open it is DiskImageMounter. I get the message that it can’t be opened because “the disk image is not recognized.” I had already changed the security setting to allow from anywhere. And I’ve upgraded to Mac OS X 10.10, which changes nothing.

You are giving not much info on how you did the install, and what went wrong.

Maybe you should read this page, to see if other/additional steps are needed: