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“GLanSync is damaged and can’t be opened”

It is not damaged, and your download is fine. That message is what macOS shows for any app that has not been through Apple’s paid notarization service yet. Here is how to open it, and why it happens.

Why you are seeing this

Shipping an app that opens with no warning requires an Apple Developer Program membership at $99 a year, plus notarization of every build. GLanSync is free during launch and has not earned that back yet, so builds go out signed but not notarized. macOS treats anything it cannot check with Apple the same way, whether it is malware or a one-person app, and the wording it picks is alarming.

Notarization is planned. Until then the steps below are the honest workaround, and you should apply the same scepticism you would to any app: only download GLanSync from glansync.com or its GitHub releases page, and check the SHA-256 published with each release if you want to be certain the file is the one that was built.

macOS 15 (Sequoia) and newer

On these versions, right-clicking the app no longer offers a way through. Use System Settings instead.

  1. Open the downloaded .dmg and drag GLanSync into your Applications folder.
  2. Open it once from Applications. You will get the warning — click Done or Cancel.
  3. Go to System Settings → Privacy & Security, scroll down to the Security section. There is a line saying GLanSync was blocked, with an Open Anyway button next to it.
  4. Click Open Anyway, then confirm with Touch ID or your password.

The line in Privacy & Security only appears after you have tried to open the app at least once, and it disappears after about an hour. If you cannot see it, open the app again and go straight back.

macOS 13 and 14 (Ventura, Sonoma)

  1. Drag GLanSync into Applications.
  2. In Applications, right-click (or Control-click) GLanSync and choose Open.
  3. The dialog now has an Open button that the normal double-click does not offer. Click it.

You only do this once. After that it opens normally.

If it still says “damaged”

This usually means the file kept its download quarantine flag — most often after downloading the .zip rather than the .dmg. Removing that flag fixes it. Open Terminal and run: 

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

That command clears the “downloaded from the internet” marker on that one app and nothing else. If you would rather not run a Terminal command, download the .dmg instead of the .zip and follow the steps for your macOS version above.

Windows: “Windows protected your PC”

Same cause, different wording. The installer is not code-signed yet, so SmartScreen shows a blue dialog with only a Don’t run button visible.

  1. Click More info in that dialog — it is small text above the button.
  2. A Run anyway button appears. Click it.

Your antivirus may also flag a brand-new unsigned installer simply because it has not been seen before. If it quarantines the file, the SHA-256 on the releases page lets you confirm you have the real build before restoring it.

Which file should I download?

Your machineFileNote
Mac, Apple Silicon (M1–M4)GLanSync-mac-arm64.dmgMost Macs since 2020
Mac, IntelGLanSync-mac-x64.dmgNative Intel build, not Rosetta
Windows 10/11GLanSync-Setup-x64.exeThe usual choice
Windows on ARMGLanSync-Setup-arm64.exeSnapdragon / Surface Pro X

Not sure which Mac you have? Apple menu → About This Mac. If the Chip line says Apple M-something, use arm64; if it says Intel, use x64.

After it opens

macOS will ask for Local Network access on first launch — that is how the app finds your lights, and it will not work without it. Screen Recording is asked for the first time you start screen sync, and needs the app restarted afterwards. Microphone is only requested if you use microphone-driven music sync.

Lights not appearing? LAN Control has to be enabled per device in the Govee Home app first — walkthrough here.

Download GLanSync — free during launch