Can I update an Mac App purchased by a different Apple ID? At work we have one Mac laptop that everyone uses to compile and test our iOS app.  The employee who originally installed XCode used his personal Apple ID, and has since left the company.

When I log in to the App Store on this PC, I can download new apps (including the Mavericks update) but when I try to update an existing app, especially XCode, it always brings up the login prompt, with the user id field disabled and prefilled with his Apple ID.

Can I update XCode without his Apple ID password?
I recently ran into this issue in a different context.  I changed my developer appleID and had xCode registered under the defunct one.  When I upgraded to Mavericks, Xcode wouldn't update, since I'd downloaded it from the Apple store under defunct AppleID.  

I removed the association with the defunct appleID by removing the receipt from Xcode:


Control-click Xcode app and "show package contents".
Move the _MASReceipt directory to the trash in order to dis-associate Xcode with the old AppleID (you'll need your Mac's admin password).
Restart Apple store and "install" (rather than upgrade).


The net effect:  Xcode will "install" (upgrade) but under your preferred AppleID.  

You do NOT need your ex-employee's personal AppleID account for this, but you do need admin rights on the machine.