Set default Finder window size What's the recommended way to set the default size of a Finder window in macOS Mojave? I've tried following advice like that given in How to set default finder window size?, but no luck. It's annoying how hard Apple make this, but even if I could edit a plist file, that would be sufficient for now...
So, it seems a year later, nobody had been able to solve this one, (couldn't find any solutions posted any website) so I decided to give it a shot. After some extensive research, I've arrived at the following solution.
macOS Version: This was tested on macOS 11.0 Big Sur and on macOS 10.15 Catalina as well
Customizing the default dimensions of the Finder window

Open the Terminal application, enable the &quot;Quit Finder&quot; menu item
defaults write com.apple.finder QuitMenuItem -bool true; killall Finder


In Finder, open a new window and configure its size/dimensions to the exact way you like it

Quit the Finder application (⌘ Q)

Launch the Finder application

When you first open the Finder application, a window is not created, which is a bit unintuitive ¯\_(ツ)_/¯


In Finder, create a new window (⌘ N)

The position/dimensions of this window should be exactly the way you like it. Finder determined what the position/dimension ought to be using configurations stored in the ~/.DS_Store file. Every time a Finder window is moved or resized, the ~/.DS_Store file will be written to.



Any future windows should default to opening with this size/position on the screen.
Note: If you try to open a Finder window on a larger screen, don't expect the window to be centered. Finder doesn't store the relative offset of the window to the screen, it stores the X/Y pixel offset from the top-left corner
Note: Don't try and be clever by removing write access to ~/.DS_Store, it didn't work out for me. Finder's reaction to losing write access is to ignore the ~/.DS_Store file completely, causing every new window to open with the factory-default window configurations