It would appear that the 8.5 player for Mac doesn't support local loading in AS3 (at least for Sound, I haven't tested other objects yet). This makes a certain amount of sense, being that there is no dev environment yet, so local testing isn't really expected. However, if you're using my context menu plug-in, or one of the various other options to compile AS3 on the Mac, you'll probably want to be able to test without uploading to a server.

The solution is simple, but it took me a while to narrow down the potential approaches before I found one that worked. You simply have to test your SWF through the webserver built into OSX.

To do this, turn on "Personal Web Sharing" in the "Sharing" control panel, place the SWFs you want to test in the "~user/Sites/" directory, and access them via "http://localhost/~user/SWFName.swf" from your browser. To make this a little easier, I added a "flCompile and httpTest" context menu workflow to the flCompile package, and updated the Read Me with instructions to get it working. While I was at it, I also cleaned up the flCompile scripts a bit, and made it a little easier to change the command line params for things like background color and swf dimensions. You can download the new package from the original post on flCompile.

Also be sure to check out the comments on the original post for other options for compiling AS3 on OSX.