Getting to 10.11.6
How do I upgrade to 10.11 before going to 10.11.6
How do I upgrade to 10.11 before going to 10.11.6
You're trying to install from the wrong thing, the updater, and you should be using the main installer:
Upgrade to OS X El Capitan - https://support.apple.com/HT206886 - "OS X El Capitan remains available for Mac computers that can't upgrade to macOS Sierra, or that need to upgrade to El Capitan first."
You're trying to install from the wrong thing, the updater, and you should be using the main installer:
Upgrade to OS X El Capitan - https://support.apple.com/HT206886 - "OS X El Capitan remains available for Mac computers that can't upgrade to macOS Sierra, or that need to upgrade to El Capitan first."
Check to make sure your applications are compatible.
El Capitan 10.11 Compatibility information
macOS Sierra 10.12: Compatible Apps
Also check to make sure there is a compatible driver for your printer.
Do a backup before installing, preferable 2 backups on 2 different drives.
Getting to 10.11.6