Most likely it is an issue with the connection in some way in which the download is getting corrupted therefore will not resume and is incomplete.
Originally Posted by kellyann7
Definitely update to latest Lion so 10.7.5 mostly as it has better graphics support for OpenGL which the Mac client uses and may help any network issues.
You don't need to worry about the Gatekeeper until you come to install the game from a complete download. If via Steam not sure how it works but otherwise just read the previous threads you have loked at.
One thing not mentioned I suggest to switch off the Firewall on the Mac just in case it is effecting the download. The router will most probably have it's own firewall and port settings which you may want to check if none of the following work. But is is generally more involved so try these first. If you can download some then at least it is connecting.
Not sure what your connection is but if a decent broadband one then I suggest to continue the download attempt with Progressive Downloader (you can open more than one thread in preferences may speed it or by clicking the download and select Threads and + add one if it will do this. depends on the server but think it does)
If that fails then yes try Steam. Previously it was a HUGE bloated install of 36GB+ but I see this morning that it is now a more realistic 20GB+ size download.(though still larger than direct download)
That should provide a more stable download for you.
If possible also with connection issues, if possible it is always worth trying to connect directly to the router with an ethernet cable rather than wifi which can be flaky. But if not just do the things above and I'll keep my fingers crossed for you
Post back if you need any further help. If you do so it may help to have a more detailed idea of your Mac set up
1. In the Finder click on the Apple icon on the top left of the menu bar (top of screen) and click on About This Mac > More Info....
2. Copy/Paste each line in that page, for example my setup;
27-inch, Mid 2011
Processor 3.1 GHz Intel Core i5
Memory 16 GB 1333 MHz DDR3
Graphics AMD Radeon HD 6970M 2048 MB
Serial Number N/A
Software OS X 10.8.2 (12C60)
Gaspard Strongpole - Hunter on Eldar : Mac Player - iMac/27-inch, Late 2013/ 3.4 GHz Intel Core i5/ 8 GB 1600 MHz DDR3/ NVIDIA GeForce GTX 780M 4096 MB/OS X 10.10.5