I am running iOS 15.7

I tried the terminal: chdir the the drive with the xip file. The external drive with the xip has 279GB free space Entered; xip --expand XCode-12.5 The expand failed for lack of space. I changed the startup drive to one that has more free space than my usual startup drive. Entered; xip --expand XCode-12.5 It worked! Evidently xip needs space on both the drive with the xip file and the startup drive.