Hi everyone, yesterday i migrated my little MacRuby project to 0.6 and i found a kind of strange behavior in a comparison between a string and nil. In MacRuby 0.5 the line worked as expected. I get the following error message in a comparison between a string on the left and nil on the right: can't convert nil into String (TypeError) I made a little demo project to show the problem. The string i want to compare comes out of a userInfo dictionary i get when iTunes send a notification through the NSDistributredNotificationCenter. In the demo project the error occurs, if you play, pause, or skip a song in iTunes (every time i get a notification from iTunes). So here the code in which the error occurs: def songChanged(notification) NSLog("notification.userInfo[Name] #{notification.userInfo['Name']}.") NSLog("notification.userInfo[Name].nil? #{notification.userInfo['Name'].nil?}.") NSLog("notification.userInfo[Name].class #{notification.userInfo['Name'].class}.") NSLog("notification.userInfo[Name] != nil #{notification.userInfo['Name'] != nil}") end The method receives a notification from iTunes and the last line in the method fails ( notification.userInfo['Name'] != nil ). I don't know where the problem is, but i guess the comparison should just return false. One again, in MacRuby 0.5 the line worked as expected. You can find the hole demo project at: http://github.com/michelSt/MacRubyBug Thanks, Michel -- Michel Steuwer | michel.steuwer@onlinehome.de