Hi everyone - There is probably a very obvious answer to this question, but I just can't seem to figure it out! Every time I double click my hard drive to open the window, it usually displays the sidebar. Recently, I slid my window over to hide the sidebar, and now every time I open a new window, it doesn't display the sidebar anymore. I've looked in preferences etc to see if there was a place where I could indicate "show me the sidebar every time I open a new window", but couldn't find anything.
You should be able to just double-click the vertical bar at far left edge of a Finder window to restore the sidebar. Or, click-hold and drag from the far left side toward the center and the sidebar should drag into view. Use the tiny indented dot as a guide where to click or grab.
To hide the sidebar, double-click or drag the interior vertical separator bar fully to the left.
Clicking the oblong "pill" in window's upper right will hide/reveal both the sidebar and top toolbar.
I knew how to get it back, but I just wanted to indicate in the preferences that every time I open a new window, it automatically displays the sidebar) - But for some reason, it is working now (displaying a sidebar for every new window that is opened).
Thanks for the tip.. (and, I probably qualify for the "easiest question award" on this forum) ;)