Since the latest update "Remember the current state of Tools Pane" does not work.
Regardless of if the option is checked or not, when opening a file the tools pane is open.
Windows 10 Pro 64-bit
Yasir Alam commented
This is not a fix.
But for anyone else struggling with this ridiculously stupid issue, and isn't intent on moving away from Adobe
You can solve the issue by downgrading to the 'old' Acrobat Reader:
Click on the menu tab (3 bars top left) click on "Disable new Acrobat Reader" in menu tab.
Old Acrobat Reader works with "remember current state of tools pane" option for me.
On the unexpected plus side you don't have to use the death-by-a million-paper-cuts 'new' Acrobat Reader