Updating Xcode from 4.1 to 4.2: No "Install Xcode.app" in Applications folder

I've updated Xcode from 4.1 to 4.2 in Mac App Store but Xcode is still 4.1.

In Mac App Store now, no update available anymore. Xcode in Mac App Store does not appear like installed application because the开发者_运维问答 button is labeled as "FREE" then "INSTALL APP" not "INSTALLED" as expected. When I clicked "FREE" and then "INSTALL APP", it alerts

"We could not complete you purchase

Xcode is already installed on this computer. Choose Software Update from the Apple menu to check for available updates."

I followed the instruction but there is no available update for Xcode. I also tried to restart my computer for a few times but no effect.

Edited: There is no Install Xcode in my Applications folder as well.

Is there any suggestion? Thank you.

Let me answer my question.

In my case, instead of Applications folder, Install Xcode appears in Launchpad. So if you cannot find Install Xcode in your Application folder, take a look at your Launchpad.

If I recall correctly 4.1 was before the mac app store and they may not have built in an easy way to cleanly update between the two. You could move the 4.1 app to your desktop temporarily and see if the 4.2 install will go through and install itself, or uninstall 4.1 completely (make sure your projects are not saved within). Or also see if in the mac app store it has a check for updates not the same as Software Update.