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Install

1. Download Tern-x.y.z.dmg from the latest release.
2. Open the .dmg. Drag Tern into Applications.
3. Open Tern from Applications. macOS shows a warning that the app cannot be opened because the developer cannot be verified (the wording varies by system version). Dismiss it.
4. Open System Settings › Privacy & Security. Scroll to the Security section. Click Open Anyway next to the mention of Tern. Confirm.
5. If the button is missing, in Finder Control-click Tern › Open › Open.
6. Tern does not appear in the Dock. Look for the two-window icon in the menu bar, at the top right.

The warning only appears on first launch. Later updates, from the app itself, do not ask again. Tern is signed with its own certificate; the source is on GitHub, MIT license.

Permissions

Accessibility (required)

macOS only lets Tern read window titles and bring the chosen window forward with Accessibility on. Tern does not read window contents.

1. The first time you press ⌥ ⇥, Tern asks for the permission. Click to open Settings.
2. System Settings › Privacy & Security › Accessibility.
3. Turn Tern on. If it is not in the list, click + and choose Tern from Applications.
4. Go back to Tern and press the shortcut again.

Screen Recording (optional)

Only the thumbnails on the cards. Without this permission, the switcher still switches windows; the card shows the icon. Tern does not record the screen.

In Tern Settings, request the permission. Then: System Settings › Privacy & Security › Screen & System Audio Recording. Tern may not add itself to the list: click + and choose the app. Quit Tern from the menu bar and open it again.

Input Monitoring (only if the shortcut leaks)

With Accessibility, Tern swallows the shortcut so it does not also fire in the frontmost app. On most macOS versions that is enough. If the browser still reacts to ⌥ ⇥, turn on Input Monitoring for Tern in System Settings › Privacy & Security.

Troubleshooting

The shortcut does not open the switcher

Confirm Tern is in the menu bar. Without Accessibility, the HUD asks for permission instead of listing windows. In Tern Settings, check that the recorded shortcut is the one you are pressing. Another app may have taken the same shortcut.

⌥⇥ also fires in the frontmost app

Turn on Input Monitoring, as above. Tern intercepts the shortcut on purpose; if the system will not let the event tap swallow the key, the frontmost app still sees Tab.

Accessibility after an update

From 1.1.3 on, later versions do not ask for Accessibility again: the app signature stays the same. If the switcher stops opening after an update, remove Tern from Accessibility and add it again. Only a change of signing certificate (for example, moving to a Developer ID) makes everyone grant it once more.

Automation

In the Shortcuts app: open the switcher, hide an app, show it again, change the mode. From a URL:

• tern://open opens the switcher
• tern://hide?app=com.spotify.client&for=1h hides Spotify for an hour
• tern://unhide?app=com.spotify.client shows it again
• tern://mode?name=Work turns a mode on; tern://mode turns it off

Those links do not close windows or quit apps.

Download Tern · Changelog