How to hide sidebar preview (on the right) in Finder on El Capitan I don't know since when, but I believe from some update of El Capitan, this annoying sidebar preview on the right comes up everytime I open a new Finder window.

If I hide it using the mouse, it stays hidden in the current window but re-appears when I open a new window.

The sidebar on the left is all fine, showing items as it does normally.

Logically speaking, when I have switched to the preview window option and I already see items at the top, why would I need a second one at the right?

I couldn't find anything on the internet, people are just talking about how to hide sidebar preview in the Preview app. So any help would be greatly appreciated.

The image is attached:
This is called Preview.

Type Shift+Command+p to turn it either on or off.

Alternatively open Finder's View menu and select Hide Preview / Show Preview.