Detect When Your macOS App Has Been Moved During Runtime

Sep 6th, 2019

Daniel Jalkut of MarsEdit fame released a little Swift helper to detect when a macOS app has been moved during runtime. His write-up explains everything. In short, moving an .app bundle while the app is running will inevitable result in resources not being found, and occasional also in crashes.

This or a similar helper is a practical necessity in all applications that are distributed outside the Mac App Store.

Check out RSAppMovementMonitor on GitHub.
The long defunct LetsMove used to be a tool that tried to prevent the issue by offering to move the app to /Applications upon launch from any other directory.

Links to this article

AppMover Swift Library to Move Your macOS App to the Applications Folder

Oskar Groth published a modern iteration of the “LetsMove” framework where you can show a dialog at app launch, asking the user if she wants to move the app to /Applications first.

This is still a crucial feature if you distribute downloads that unpack into the ~/Downloads folder: Gatekeeper’s App Translocation will actually start it from a random sandboxed folder. To prevent this from happening, distribute your apps as a DMG with a shortcut to /Applications to nudge your users to move the app there directly.

Get https://github.com/OskarGroth/AppMover on GitHub.

See also:
- To offset potential bugs when moving the app bundle during runtime, Daniel Jalkut wrote a tool for that.
- Michael Tsai’s overview of Gatekeeper Path Randomization.