How to install MacTeX 2015 successfully in El Capitan? I upgraded to El Capitan in my new Macbook Air. El Capitan does not allow to use /usr/texbin/ for storage so LaTeX community had to move their files to /Library/TeX. 
MacTeX 2015 is not fully compatible with El Capitan. 
There is at least some path reconfigurations which has to be done in individual programs described in the guide. 
However, I have not succeeded in getting MacTeX fully working in El Capitan. 

Fixing LaTeX in El Capitan

All stages went right but not the following with TeX Live Utility. 
I am doing the step in the guide MacTEX-2015 and El Capitan (page 3)


  For previous versions of TEX Live Utility open TEX Live
  Utility→Preferences and click on the Choose. . . button as in Figure
  (4). That opens a file chooser. Type Shift-Cmd-G, enter /Library/TeX
  into the dialog box as shown in Figure (5) and then press Return.
  Finally DoubleClick on texbin.


I get



After Unsuccessful Setup-2015.pkg

I run rm ~/Library/Preferences/com.googlecode.mactlmgr.tlu.plist to delete the changes made by the applicaiton Setup-2015.pkg proposed by hakaze, because of infinity loop when starting Tex-live with those changes. 
I found the Library/TeX/texbin eventually. 



How can you set up MacTeX 2015 successfully in El Capitan?
You are misreading the guide when defining the path for TeX programs in TeX Live Utility.


In TeX Live Utility, open Preferences
Click on "Choose"
Do one of the following


press Shift-Cmd-G, type /Libary/TeX, click on "Go", double-click on texbin and then click on "Choose"
press Shift-Cmd-G, type /Libary/TeX/texbin, click on "Go" and then click on "Choose"