from Tex site:
"We have two reports from users who updated from Mavericks to Yosemite rather than installing Yosemite on a fresh disk partition. Both users report that when the installation was almost complete, there was a long delay with no feedback: one hour in one case and twelve hours in another. During this delay, the installer's log file reported that it was copying TeX Live files one by one from "/Volumes/Hard Disk/Recovered Items/usr/local/texlive" to "/Volumes/Hard Disk/usr/local/texlive"."
"A colleague tells me that the way to update to Yosemite, with one or more TeX installations installed, is to first
mv /usr/local/texlive ~
do the install, then
mv ~/texlive /usr/local
"This avoids the installer archiving then re-installing that hierarchy *file-by-file*. This kind of approach may be useful with other subdirectories of /usr/local as well."
This solution moves the texlive directory to the User's home directory, installs Yosemite, and then moves the texlive directory back to its proper location. In more detail, the appropriate commands are as follows (spaces in these commands are essential, so copying the commands may work better than retyping them):
sudo mv /usr/local/texlive ~
install Yosemite
sudo mv ~/texlive /usr/local