There are a number of settings you can change to control how the macOS Dock looks and behaves, which can help enhance your usage of the macOS UI element. Here's how to access them.
The Dock
History
The Dock has been around since macOS was originally an operating system at Steve Jobs' second company, NeXT. The original Mac had no dock, and its inclusion in macOS when Apple bought NeXT in 1997 was a highly contentious issue at Apple.
When it was included in macOS, several additional options were added so users could customize the Dock to their liking - including hiding it completely.
Original NeXStep desktop - with Dock shown on the right.
Customizing the Dock in macOS
Today, to customize the Dock in macOS, go to System Settings->Desktop & Dock from the Apple menu in the macOS menubar. Most of the Dock-related items are at the top of this settings pane:
Chose "Desktop & Dock" on the left.
At the top of the Desktop & Dock pane are two sliders. One controls the Dock size, while the other the Dock magnification level when you mouse over it.
If you cram a huge number of apps into the Dock, the Finder will reduce the size of the icons to their smallest size to fit everything in.
You can also turn magnification off entirely so the icons don't move when you mouse over them.
Next is a popup menu which changes the position of the Dock onscreen. You have three choices: Left, Bottom, or Right, with Bottom the default in macOS out of the box.
The next item, Minimize windows using, controls which animation is used to reduce Finder windows into the Dock when you click the yellow minimize buttons in windows. You have two choices: Genie or Scale.
Double-click a window's title bar to: controls what happens to a window when you double-click its title bar. You can turn this option off, zoom the window, or minimize it.
If you turn on the next item, Minimize window into application icon, Finder shrinks the window into its parent app and adds it to a popup menu when you click a window's yellow minimize button. You can access the shrunken window by Control-clicking or right-clicking the app's icon in the Dock.
Automatically hide and show the Dock hides the Dock by default, but shows it if you mouse over the edge of the screen where you have set the Dock to appear. Users who opine that the Dock is in the way and blocks the screen can use this option to hide and show the Dock at will with a simple mouse-over.
Animate opening applications, when turned on causes an app's icon to bounce up and down in the Dock as the app is launched. Turn this off for better responsiveness by not using the launch animation.
Show indicators for open applications causes the Dock to display a tiny dot underneath any app which is currently running. This can be handy to see at a glance which apps are running simply by looking at the Dock.
Show recent applications in Dock causes the Dock to display apps that were recently used, but are now closed, on the right side of the Dock next to the Trash.
Most of the rest of the settings in this System Settings pane apply to the Desktop, not the Dock so we'll skip those.
Adding and removing items
To add an app to the Dock drag it from anywhere in the Finder into the Dock. It will be inserted where you drop it.
You can also drag multiple items at once and drop them to add them all to the Dock.
To remove an item, click and hold, then drag it away from the Dock until the small "Remove" badge appears, then release the mouse button.
To add files or folders to the Dock, drag them into the Dock, but to the right of the divider item on the right side. All documents and folders are stored to the right of the divider, but to the left of the Trash.
No matter what you do, the Trash always remains on the far right side of the Dock.
Customizing folders
Once folders are added to the Dock, you can Control-click or right-click them to get a popup menu for customization. Using that menu, you can change how folder items are sorted, display a folder as a Stack, change how contents are viewed when you click the item, and other options.
Control-click a folder to get the popup mneu.
If you set the View content as menu option to List, the next time you click the folder, Finder displays a popover with a simple vertical list of folder contents in it. This can be useful for drilling down through subfolder hierarchies in an instant.
If you set the View content as menu option to Fan, when you click the folder in the Dock it pops up the folder's contents accordion-style, complete with each item's thumbnail and name. If you set it to Grid, when you click the folder, Finder displays a popover with a grid of folder contents:
Grid view when Control-clicking.
Dock Options menu
If you Control-click or right-click an app in the Dock, you get a small popup menu. One menu item on Dock popup menus is Options. If you select it, you get a submenu with three more items:
- Remove from Dock
- Open at Login
- Show in Finder
The first item is self-explanatory.
If you select Open at Login, Finder adds a Login Item for this app to the list of items to open when you first log in.
The next time you log in, any items added to Login Items will be run automatically. To stop an item from running at login, select the same menu item again.
If you select Show in Finder, Finder opens the app's parent folder on the Desktop.
The Preferences file
All the settings for the Dock in macOS are stored in an XML file named com.apple.dock.plist which lives on your Startup Disk in /Users/~/Library/Preferences/.
You can customize the Dock by editing this file, but be aware if you damage the structure of the file, or change a critical setting to some value macOS doesn't understand, you can prevent the Dock from displaying at all.
You may want to make a backup of the file just to be safe before making any changes to it.
Inside the Dock .plist file is an array named "persistent-apps". This array contains all the apps displayed to the left of the divider in the Dock.
If you have a huge number of apps in the Dock and want to remove a lot of them all at once, in bulk, Control-click items in this array, delete the items, then save the file and Restart.
When the Finder loads the Dock next time, the list of apps displayed will be updated.
To reset your Dock to its pristine original state, delete this file, then restart your Mac. In fact, you can save multiple copies of the Dock .plist file to a folder, then just replace the existing one with a saved copy and restart in order to change how the Dock looks for different work scenarios.
Restarting the Dock
You may have noticed if you Force Quit the Finder, it doesn't always reload any new Dock state when the Finder runs. This is because the Dock is actually its own separate process which runs independently of the Finder.
If you run the macOS Activity Monitor in the /Utilities folder and search for "Dock", you'll see the Dock process running. You can quit and restart it by selecting it in the process list, then clicking the small X (Stop) button in Activity Monitor's toolbar.
If Finder notices the Dock quit, it will automatically relaunch it in a few seconds.
You can also force-restart the Dock in macOS's Terminal by typing:
killall Dock and pressing Return.
Possibilities
Apple hasn't really updated the Dock in a long time - other than cosmetically. A few additions could make it even more useful than it already is.
For example, being able to group apps like in iOS, being able to multi-select apps in the Dock for bulk removal or reordering, a "Move to" menu item to send an app to another folder on disk, and even a "Check for Update" on the App Store option.
Displaying a subset of the Finder's Get Info data in a popover would also be nice - especially the app version number.
There are lots of ways to customize the Dock in macOS and using these options you can make it behave just the way you like.