I was trying to update my MacTeX this afternoon. However, TeX Live Utility complained that it couldn't find TeX Live root using kpsewhich --var-value=SELFAUTOPARENT. I checked this in the Terminal, and kpsewhich worked well. (see the screenshot below) I had also checked other mirrors of CTAN, but the problem went on.
System version:
- Mac OS X: 10.9.5
- MacTeX: 2014
Any clues would be appreciated.

sudo tlmgr update --selfat the Terminal help? If so, this is a 'known issue'. – Joseph Wright Dec 27 '14 at 10:02