How Uncork works

Updated 8 October 2026 · Uncork 1.1.2

Short version: Uncork runs Windows games from Steam and Epic on Apple Silicon Macs through a compatibility layer and Apple's graphics libraries — the same base other Mac apps use. What we built on top: graphics chosen per game by its DirectX version, Find out why for a game that crashed, game recipes, Game Mode for every Windows game, community reports on about 380 games. All of that is free. Uncork Pro (€19 once) adds the mouse read straight from the device, Even frames, an overlay with measurements and wheel force feedback.

Setup

One button installs the compatibility engine, the graphics libraries and Windows Steam into a separate folder (a “bottle”). No Terminal and no Homebrew. Apple's D3DMetal is not bundled: the app downloads it only after you accept Apple's licence in its window.

Graphics for each game

Uncork reads the game's files and picks how it draws:

Game	What “Auto” picks
DirectX 10–12	D3DMetal or DXMT — whichever the bottle uses
DirectX 9 and older	built-in graphics through OpenGL (Half-Life 2, Portal 2, Teardown)
Assetto Corsa with Custom Shaders Patch	DXMT: on D3DMetal the patch draws pink squares

The choice can be changed for a single game, and it does not touch the others. DXVK (through Vulkan) is only enabled by hand. A choice you made yourself always wins over a recipe, and a recipe wins over “Auto”.

When a game does not start: Find out why

After a crash, the Find out why button reads the log and names the cause it recognises: the game lacks .NET or a DirectX function, Windows fonts are missing, the Steam overlay crashes the game, a display was connected after Steam started, iCloud can remove the game's settings, the gamepad is missing or shows up twice, a DirectX 9 game needs other graphics. Each fix says what it will change before it runs, and can be undone.

Game recipes (since 1.1)

A recipe is a description of what one specific game needs: launch options, a setting in the registry, a config file. It is applied on top of the usual fixes and has its own undo. Simple recipes apply by themselves; the rest show a list of what will change first. The first are Portal 2 and Half-Life 2.

Will my game run

14 games are tested by hand on a MacBook Pro 14" with M3 Pro. For about 380 more the app shows community reports (“reported to run” or “reported not to run” with the snapshot date) from the open CC0 highball-db — built into the app, no network needed. Our own tests always take priority. The same check is on the main page.

During the game

macOS Game Mode turns on for Windows games: Uncork runs each game as a Mac app of the “games” category.
While a game runs, Steam's browser (store, friends, overlay) moves to the efficiency cores and leaves the performance cores to the game.
A DualSense or Xbox controller can drive the Mac's pointer; the controller mode per bottle fixes a gamepad that is missing or doubled.
“Create app” turns a game into its own Mac app with its cover as the icon, for the Dock and Spotlight.

What Pro adds (€19 once, 7-day trial)

Mouse from the device. macOS hands the mouse to apps once per display frame: in one 20-second recording (MacBook Pro 14" M3 Pro, 120 Hz, a 1000 Hz mouse, 25 September 2026) 843 movements a second arrived as 119 batches. Uncork's display driver reads the mouse from the device (HID) while the game hides the cursor. On a trackpad or a 125 Hz mouse there is usually no difference. Details: Why aim feels floaty on a Mac.
Even frames for single-player games: frames are paced to the 4.17 ms grid of a ProMotion display. In CS2 at 80 fps, 87% of on-screen intervals were even, versus 18% without it. Not for competitive shooters.
An overlay with fps, frame evenness, latency to the screen and mouse rate; Assetto Corsa in one click; Logitech G923 force feedback.

What Uncork does not do

Games with kernel-level anti-cheat do not run (Valorant, Fortnite, Apex Legends, PUBG and others). Uncork does not bypass protections.
It needs Rosetta 2: Windows games are x86 code. On macOS 28 Apple keeps Rosetta only for older games — what this means.
No upscaling like DLSS or MetalFX.
It is not faster “by itself”: frame rate depends on the game and the graphics library. All our measurements are on one Mac, the M3 Pro; there are no independent tests yet.