This isn't going to fly for us when we upgrade, users switch back and forth between old and new branches. We just went through this with the error:

Exception message: [Errno 1] Operation not permitted: '/Users/pantsdev/Development/java/.pants.d/compile/zinc/252d64521cf9/testing-support.src.main.java.aux-lib/current'

and I'm still getting support queries about it. Once again,

./pants clean-all

seems to work around it for the global lock. I'm not sure about the ivy lock yet - testing.