Installing on macOS

Download the DMG matching your Mac: lmc_<version>_arm64.dmg for Apple Silicon (M-series) or lmc_<version>_x86_64.dmg for Intel. Open the DMG and drag LAN-Messenger.app to /Applications.

First launch is blocked

On the first launch macOS may refuse to open the app with one of these:

• “LAN-Messenger can’t be opened because Apple cannot check it for malicious software.”
• “LAN-Messenger is damaged and can’t be opened.”

This is Gatekeeper, not a broken download. The app is ad-hoc signed and not notarized, so macOS cannot verify the developer identity and errs on the side of blocking. It happens once per install, not on every launch.

Allow the app to run

Clear the quarantine attribute once:

sudo xattr -dr com.apple.quarantine "/Applications/LAN-Messenger.app"

After that the app launches normally from Spotlight, Launchpad, or the /Applications folder. To verify right away, open it from the terminal:

open "/Applications/LAN-Messenger.app"

What you don’t need

• A manual codesign: the bundle already carries its signature; signing it again locally changes nothing.
• Re-downloading the DMG: the warning is about developer identity, not a corrupted file.
• Disabling Gatekeeper system-wide (spctl --master-disable): never needed for this, and it lowers protection for everything else.

Removing the warning entirely requires an Apple Developer ID and notarization of every release; until then the one-time command above is the supported path.

If it still doesn’t start

Open an issue with your macOS version, your chip (Apple Silicon or Intel), the app version, and the exact message text macOS shows.