\Documents and Settings\[username]\Application Data\Ableton\Live x.x.x\Preferences\Log.txt
Windows Vista, Windows 7, Windows 8
Mac OS X
On recent versions of OS X, the user Library folder is hidden. The easiest way to temporarily reveal the ~/Library folder is to open Finder. On the menu bar, at the top, select Go to reveal the drop-down menu and then hold down the Option key (marked ALT) and you will see the ~/Library folder appear. You may now select this ~/Library folder with your mouse or trackpad.