Mac OS X Hangs from Lightroom

More often than I'd like lately, when I import photos into Lightroom (from an SD card in a USB reader) it hangs my whole Mac.

I can understand how Lightroom could crash, but I'm a little baffled that it manages to freeze the whole operating system. You get the spinning beachball and you can't to anything - can't switch apps, can't pull down menus, can't do Ctrl + Eject to shutdown.

At first I thought it was because I would start to view photos while it was still downloading, so I quit doing that, but it's still happening.

The strange thing is that Lightroom is normally very stable. It doesn't crash or hang when I'm working in it, no matter what I do. I suspect this is more of an OS bug, or at least a bad interaction between the app and the OS.

This seems to have become a problem recently, perhaps related to either Lightroom updates, or OS X updates, or both. (That's one of the downsides of all these automatic updates.)

I wonder whether it has someting to do with importing directly from the SD card through USB. Not that that is an excuse for the OS to die, but I could see where there would be some low level device stuff going on. Maybe I should copy the files to the Mac and then import from there. Although that's quite a bit more hassle since Lightroom auto-detects memory cards and goes straight to Import. However, I think you can set up Lightroom to "watch" a directory, so maybe I could do that and copy to that directory.