Dawn Johnsen

David, I tried having attack set to left click, and left click did not work for attack either. What I did try was setting pick block to my "command" key (on mac), and now the left-click seems to be working, at least on survival, singleplayer (have not yet tested in on other modes). Doesn't seem like the most suitable fix, but at least I can play now.

Shaunna--what happens when you try setting pick block as any other key? Just curious.

I have the same problem when updating to 1.4.2, although, I use a Mac OS X v10.6.8, Java updated. I also have no mods running, nor texturepacks. The left click (Button 1) is not working at all. I can't pick things up out of my inventory using left click. Right-click (double-click for mac) does divide stacks in half and places things one at a time, so agreed – picking up whole stacks or one item at a time is impossible. When I revert back to the prior update, it works fine.