Fixes OS X El Capitan Install Problems
One of the complaints we saw when OS X El Capitan first arrived was that some users ran into issues installing the upgrade. The problem was not an issue for every user, but it was enough of an issue to get the attention of Apple.
In the OS X 10.11.1 update Apple announces that the installer reliability is improved. If you are still on OS X Yosemite, you should now be able to upgrade to OS X El Capitan easier thanks to OS X 10.11.1.