Halo v1.0.3

Halo v1.0.3 — live previews for fullscreen apps.

What's new

• Fullscreen apps get real window previews. Hovering an app that's fullscreen on its own Space now shows a live preview of that window, instead of falling back to an icon card. ScreenCaptureKit can only screenshot windows on the active Space (it fails with error -3811 for everything else), so Halo now falls back to a WindowServer-side SkyLight capture that renders a window regardless of Space — the same approach AltTab uses. Best-effort and isolated like all of Halo's private-API use: if it ever fails, you get the icon card as before.
• Other-Space and minimized windows too. The same fallback covers windows on any other Space, and minimized windows now preview their last-rendered content.

Update

Already on Halo? Click the menu-bar icon → Check for Updates… and it'll download and relaunch into this version. Or grab Halo.app.zip below.

Requires macOS 26 (Tahoe) on Apple Silicon. Not Mac App Store eligible (self-build / sideload only).

macOS says it "could not verify Halo is free of malware"?

That's expected for a downloaded Halo.app.zip — the release is signed with an Apple Development certificate, not a notarized Developer ID one, so Gatekeeper blocks the first launch. Two ways past it:

1. Terminal (recommended). Move Halo.app to /Applications, then strip the quarantine flag:

   xattr -dr com.apple.quarantine /Applications/Halo.app

   This also prevents Gatekeeper App Translocation, which would otherwise break the permission grants and the in-app updater.
2. System Settings. Try to open Halo once (let it get blocked), then go to System Settings ▸ Privacy & Security, scroll down to the "Halo was blocked" notice, and click Open Anyway. (On macOS 26 the old right-click ▸ Open bypass no longer works for unnotarized apps.)

More detail in the README.