The latest installed version of OS X was El Capitan which crashed during a Sierra upgrade. Internet recovery mode worked somehow to land me to install download and install a new OS but it's Mountain Lion, which came installed when I bought the Macbook few years back However, it's rejecting to install on current SSD drive as shown in pic. Start and complete a backup with Time Machine before beginning. Alternatively, perform your own.

Reinstall Os X El Capitan

I have a few MacPro3,1's at my school I'd like to update to El Capitan 10.11.6. Currently they're running 10.5.8. I've got really slow WiFi-internet access, but the MacPro's do not have Airport. How do I attack this?
I want to make an up-to-date USB-install stick. I know I need to get hold of El Capitan, but my personal MacBook Pro is still running Mavericks. Mercury outboards repair manual. I can only update to Sierra. Download procite. So I have to find an El Capitan-running Mac, but if I manage to get hold of the El Capitan-installer, it will be tied to their Apple-ID, right? Will El Capitan install without internet access?