I have a mac that I primarily use for xcode (so I am not really familiar with how Macs work). I develop iOS apps. Of late I have been running out of space. I delete as much as I can and the space keeps filling up. I have an external drive that I can move thing to. So I moved a bunch of stuff last night so I had 8 GB free and tried to do the update. In the morning it said the update failed because I don't have enough space (400 MB available). I deleted Xcode 4 which freed up 10 GB of space. Immediately the available space started to drop and now it is down to 8 GB. The only thing that seems to be running is Application update.
Question: When an application update fails does it keep the space it is using? That is, do I have many copies of multi-GB partial downloads of xcode hidden somewhere on my disk? if so, where?