Automatically start multiple user sessions when OSX starts I need to get several users session logged-in as soon as the computer starts. Manually I would have to log into the first user and then start switching to each one to open their respective sessions. I need to automate this process. At the end sessions must remain open so each will have some program instances running.

Thanks!
Assuming there are no passwords, you can have each user session open another one when starting, using CGSession. I did not try it with Yosemite, but it does work for me with El Capitan.


Log in as user1.
Create an empty file named “logall.sh”, in a folder where the user won’t see it.
Make the file executable (open Applications/Utilities/Terminal, type chmod 777  (with the trailing space); drag the file’s icon in the Terminal window; press Return).
Make the file always open with Terminal (right-click on the file’s icon; select “Open with…/Other”; check “Always open with”; select Applications/Utilities/Terminal).
Open the file in TextEdit.
Set the file’s contents to the following, and save:

"/System/Library/CoreServices/Menu Extras/User.menu/Contents/Resources/\
CGSession" -switchToUserID `id -u user2`



Repeat for each user except user1. Set user1 to log in automatically on startup (System Preferences/Users and Groups/Options/Automatic login/user1).