Speed up the macOS Dock animation

If you auto-hide the Dock, macOS makes you wait twice: a delay before it starts sliding, then the slide itself. On a machine that's otherwise fast, that lag is the one thing that feels slow. Two defaults tweaks remove both.

Prerequisite

Turn on Automatically hide and show the Dock first, under Settings → Desktop & Dock. These tweaks only affect the auto-hide behavior, so there's nothing to see until the Dock actually hides.

The command

Paste this into Terminal:

defaults write com.apple.dock autohide-time-modifier -int 0
defaults write com.apple.dock autohide-delay -float 0
killall Dock

The Dock will flicker once as it restarts, then show and hide with no animation at all.

What each line does

• autohide-time-modifier -int 0 sets the show/hide animation duration to zero, so the Dock appears and disappears instantly instead of sliding.
• autohide-delay -float 0 removes the pause before the Dock starts hiding once your cursor leaves it.
• killall Dock restarts the Dock so the changes take effect right away.

Reverting

To go back to the default behavior, delete the two keys and restart the Dock:

defaults delete com.apple.dock autohide-time-modifier
defaults delete com.apple.dock autohide-delay
killall Dock

Prefer a slightly slower snap over instant? Set autohide-time-modifier to a small value like 0.15 instead of 0.