GitHub - uncSoft/Mousetrapped: Menu bar panic button that rescues a trapped, hidden, or lost mouse cursor, even when Universal Control carried it to another Mac

A tiny, free, open-source macOS menu bar app that rescues your mouse cursor when it gets trapped, hidden, or lost, including when Universal Control has carried it off to another Mac.

brew install --cask uncSoft/mousetrapped/mousetrapped

Or grab the notarized build from the latest release.

The bug it fixes

On macOS, when a nearby Mac has Universal Control / mouse sharing enabled (made worse by remote-control tools like ScreenConnect), the cursor can get "eaten": some window captures pointer focus, hides the cursor, and leaves you in no-mouse limbo. Or the pointer crosses to the other Mac and something over there swallows it.

Under the hood the cursor usually isn't gone. It has been disassociated from the mouse (CGAssociateMouseAndMouseCursorPosition(false)), hidden by a process that never restored it, or routed to another machine. Mousetrapped forcibly undoes all of that.

What it does

Press the hotkey (⌃⌥⌘M by default) or shake the mouse hard left-right, and Mousetrapped will:

Re-associate the mouse with the on-screen cursor (undoes pointer capture)
Warp the cursor to the center of your chosen display (primary by default)
Post a synthetic mouse-move so the window server and frontmost app re-evaluate cursor visibility
Pulse a red locator ring at the destination so you can spot the cursor
If the pointer is on another Mac (Universal Control): restart the UniversalControl agent, which forces macOS to bring the pointer home, then warp it to your chosen display

Remote-pointer detection compares the raw HID device stream against the local session's event counters. If the physical mouse is moving but the local session sees nothing (or the cursor is parked at a screen edge, where Universal Control leaves it), the pointer is on the other Mac.

Menu bar controls

Rescue Cursor Now: manual trigger
Rescue To: primary display or any connected display
Shake Mouse to Rescue: toggle shake detection
Shake Sensitivity: slider from hair-trigger (right: 3 quick flicks) to deliberate (left: 7 vigorous strokes). At every level a shake means rapid, rhythmic, mostly horizontal reversals; slow or diagonal movement never counts, so ordinary mousing can't trigger a rescue.
Work Across Macs…: enables raw HID monitoring (see Permissions)
Launch at Login
Check for Updates… / Check Automatically: a lightweight check against GitHub's latest release (no Sparkle, nothing auto-downloaded). If a newer version exists it points you at the brew command or the release page. The automatic check runs on launch at most once a day and can be turned off.

Install

With Homebrew:

brew install --cask uncSoft/mousetrapped/mousetrapped

Or download the notarized build from Releases.

Or build from source (requires Xcode command line tools):

git clone https://github.com/uncSoft/Mousetrapped.git
cd Mousetrapped
./build.sh            # or ./build.sh --universal for arm64 + x86_64
cp -R dist/Mousetrapped.app /Applications/
open /Applications/Mousetrapped.app

build.sh signs with your first available Apple Development / Developer ID identity (override with CODESIGN_IDENTITY=...), falling back to ad-hoc. A stable identity matters: macOS ties the Input Monitoring grant to the code signature, so ad-hoc builds lose the grant on every rebuild.

Permissions

Mousetrapped runs at three privilege levels, using the lowest one that works:

No permissions: the ⌃⌥⌘M hotkey (Carbon RegisterEventHotKey) and the menu bar button always work for local rescues.
No permissions (usually): shake detection via an NSEvent global monitor.
Input Monitoring (opt-in via Work Across Macs…): raw HID monitoring with IOHIDManager. This watches the physical mouse and keyboard below the layer where Universal Control captures input, so shake and hotkey detection (and rescue) work even while the pointer is controlling another Mac. Grant it under System Settings → Privacy & Security → Input Monitoring, then relaunch the app.

Configuration beyond the menu

The hotkey is stored in UserDefaults as a Carbon key code + modifier mask. Example: set it to ⌃⌥⌘R (key code 15):

defaults write dev.mousetrapped.Mousetrapped hotKeyCode -int 15
defaults write dev.mousetrapped.Mousetrapped hotKeyModifiers -int 6400
killall Mousetrapped && open /Applications/Mousetrapped.app

Modifier mask is the sum of Carbon flags: ⌘ 256, ⇧ 512, ⌥ 2048, ⌃ 4096 (6400 = ⌘ + ⌥ + ⌃).

Debugging: the app logs events to the unified log (subsystem dev.mousetrapped.Mousetrapped; view with log stream --predicate 'subsystem == "dev.mousetrapped.Mousetrapped"' --level info). To also mirror to ~/Library/Logs/Mousetrapped.log, and for per-stroke shake diagnostics:

defaults write dev.mousetrapped.Mousetrapped debugLogging -bool true
defaults write dev.mousetrapped.Mousetrapped shakeDebug -bool true

Troubleshooting: "Work Across Macs" stops working after an update

macOS binds the Input Monitoring grant to an app's code-signature identity (its designated requirement). Mousetrapped's released builds all share one stable Developer ID identity, so the grant is meant to carry across updates.

Two things can still break it:

You granted permission to a differently-signed copy. A build you compiled yourself with a different certificate (e.g. an Apple Development cert) has a different designated requirement than the released Developer ID build, even though the bundle identifier is the same. macOS then holds conflicting Input Monitoring state and the grant flaps on update. build.sh now prefers your Developer ID identity to avoid this; the released cask build is always Developer ID signed.
A TCC glitch after replacing the bundle. macOS sometimes keeps showing the app as allowed while silently not delivering input. Mousetrapped detects this (input reaches the Mac, a mouse is attached, but the raw HID stream is dead) and offers to help.

Clean fix, after which updates should persist:

tccutil reset ListenEvent dev.mousetrapped.Mousetrapped

Then relaunch Mousetrapped and enable it once more under System Settings → Privacy & Security → Input Monitoring.

Trackpad vs. mouse across Macs

Shake and hotkey both rescue a lost cursor on the Mac they run on, trackpad or mouse. Across Macs (Universal Control), there's one difference:

Hotkey (⌃⌥⌘M) always works, trackpad or mouse — your hands are on the keyboard, so the reclaimed pointer is free to come home.
Shake works across Macs with a mouse, but not a trackpad. A trackpad emits no raw pointer data (macOS synthesizes motion from multitouch), and the shake gesture is itself trackpad movement that keeps driving the pointer — so it can't pull the cursor back from another Mac. On a trackpad-only Mac, Mousetrapped points this out once and steers you to the hotkey for cross-Mac rescues.

Limitations

Restarting Universal Control to reclaim the pointer drops the Universal Control link for a moment; push through the screen edge to reconnect. That trade-off is the point: it's a panic button.
If another process hid the cursor via CGDisplayHideCursor and is truly wedged, macOS scopes that hide to the offending process; the rescue restores control and shows you where the cursor is, but killing the wedged process is the final fix.
VMs or remote sessions that grab the pointer at a lower level have to release it themselves.
Trackpad only laptops with no mouse attached controlling a remote mac via push through edge must use the keyboard hotkeys, as the touchpad eats the shake detection inputs for the host mac

License

PolyForm Noncommercial 1.0.0: the source is free to use, modify, and share, but not for commercial use. You can't sell it or ship it inside a paid product.