I just made a fresh install of OS X Mavericks and got Tex Live Utility through their Google Code website. The strange thing is that it is in chinese language. And I can't find the button to change it. Anyone else having this problem? Or anybody who knows where to change the language?
[Tex/LaTex] Tex Live Utility (Mac Os X): language problem
mactexliveupdating
Related Solutions
You don't need to write to Herb for a fix. Credit goes to Bruno Voisin for finding the solution to this. Some background is here:
https://github.com/amaxwell/tlutility/issues/17#issuecomment-111517743
I think the simplest solution is here, requiring use of the Terminal:
http://tug.org/pipermail/tex-live/2015-June/036927.html
cd /tmp
curl 'https://www.tug.org/svn/texlive/trunk/Master/release-texlive.txt?revision=36787&view=co' > release-texlive.txt
sudo cp release-texlive.txt /usr/local/texlive/2015
Each of those three commands should be on a single line; the second is wrapped on this page. An updated version of MacTeX should be making its way around the CTAN mirrors right now.
Open TeX Live Utility's Preferences window and ensure that the path is set correctly for MacTeX. Use the button to choose /Library/TeX/texbin or drop that folder on the path bar. 
Best Answer
In the Language and Region system preference there should be a list of preferred languages. You can add or delete languages as makes sense for you. If a particular application isn't localized for the main language you have chosen, it will go down the list of languages until it finds a language for which it is localized. Make sure that the list of languages in your preferences makes sense for you.
This preference has changed in Mavericks, so it's possible that the issue never came up before.