Stacks (Mac OS)

Stacks are a feature of the Dock in Apple's macOS that lets a folder placed in the Dock display its contents directly from the Dock. A folder in the Dock can be displayed either as a folder icon or as a “stack” of items, and its contents can be shown as a fan, grid, or list, with multiple sorting options.¹

Stacks were introduced in Mac OS X Leopard (10.5) and were previewed at Apple's Worldwide Developers Conference (WWDC) in 2007. Apple demonstrated a default Downloads stack in the Dock to provide quick access to downloaded files.²

In the initial release of Leopard, Stacks supported fan and grid views. Mac OS X 10.5.2 added a list view and additional options such as displaying a Dock item as either a folder icon or a stack.³

Reviews of Mac OS X Snow Leopard (10.6) noted that Stacks in grid view became scrollable and could display the contents of subfolders within the stack interface, reducing the need to open a separate Finder window for navigation.⁴

A stack is created by dragging a folder to the right side of the Dock (the side that contains folders and the Trash). Selecting the stack displays the folder’s contents; users can open items directly, or choose an option to open the folder in Finder.¹

Using the stack’s shortcut menu (for example, by Control-clicking the stack), users can change the stack’s view style (fan, grid, or list), choose a sort order, and switch the Dock item’s appearance between a folder icon and a stacked-items icon.¹

In macOS Mojave (10.14), Apple introduced a separate feature also called Stacks (often described as “Desktop Stacks”), which automatically groups files on the desktop into expandable piles to reduce clutter.⁵ Desktop stacks can be enabled from the Finder “View” menu when the desktop is active, and can group items by kind and other attributes.⁶