The main question: I have two partitions in my HD (the original "Macintosh HD" and a new one "macOS"). If in "macOS" I have the OSX running – and actually booted in it –, can I erase the "Macintosh HD" partition or will there be problems?
The situation: I need it because suddenly my "Macintosh HD" stopped booting, every time I turned my mac on, it stopped in the first loading screen. I used the Recovery Mode and tried to restore the partition, but no success on it. I then reinstalled OSX in a new partition ("macOS"), so that I could launch my OS successfully. In this new partition, everything is ok. The problem is: right now, I have a 400GB partition not working.
I am not sure if the original Macintosh partition carries some important stuff for the launch system or if it can be erased (since I have another running partition).