[fv]

1.
Can not assign a folder for the mxs to export the render to.
Workaround, make a new folder on disk and put any file in there. An empty folder can not be chosen since the dialog only gives you the option to open a folder while only files can be chosen.

This happens to me when I try to lokate the folder the mxs export for renderings need to be chosen.

2.
My renders seem to start very dark until level 2 is reached. The preview in Maxwell looks sunny and perfect but the SL1 is praktically black in Maxwell. Normally I got a good view already at SL1. Not a problem of course but different.

[JDHill]

1. Yes, I have disabled my custom dialogs on OSX, at least until I can reproduce the problems people have commonly experienced with them. This means you are now using the chooser dialog supplied by SketchUp's Ruby API, where in order to choose a folder, you need to choose a file.

2. I would have to assume such a difference to be due to changes in the engine itself.

[JDHill]

If you like, here is a file which allows the custom browsers to be used on OSX. Just unzip it and put the maxwell.mod.rb file in your SketchUp plugins folder, next to your maxwell.rb file.