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macOS install help

Fix “Sheet Image Downloader.app is damaged and can’t be opened” on macOS.

If macOS blocks the app after you drag it from the DMG into Applications, remove the quarantine flag and open the app again.

Takes about 30 secondsFor macOS Gatekeeper warningsNo reinstall required
Use this only after downloading from sheetimagedownloader.com. This command removes macOS quarantine metadata from the installed Sheet Image Downloader app. Do not run it on apps from untrusted sources.

Why this warning appears

Some macOS versions attach a quarantine attribute to apps downloaded from the web. When the app is distributed as a direct DMG outside the Mac App Store, Gatekeeper may show a message such as “app is damaged and can’t be opened” even after the app has been copied correctly into the Applications folder.

The fix is to remove the quarantine attribute from the installed application bundle, then launch it again from Applications.

Fix steps

1. Install from the DMG first.
Open the downloaded DMG and drag Sheet Image Downloader.app into the Applications folder.
2. Open Terminal.
Use Spotlight search and type Terminal, or open Applications → Utilities → Terminal.
3. Run the command.
Copy and paste the command below, then press Return.
xattr -cr '/Applications/Sheet Image Downloader.app'
4. Open the app again.
Go to Applications and double-click Sheet Image Downloader. If macOS asks for confirmation, choose Open.
5. Keep the app in Applications.
Running it from Applications avoids path issues and keeps future launches simpler.

If macOS still blocks it

  • Make sure the app path is exactly /Applications/Sheet Image Downloader.app.
  • If you renamed the app, either rename it back or update the command with the new app name.
  • Delete the old app, re-download the DMG from the official download section, drag it into Applications, then run the command again.
  • Open System Settings → Privacy & Security and check whether macOS shows an “Open Anyway” option.
What the command does: xattr -cr clears extended attributes recursively from the app bundle. In this case, it removes the quarantine metadata that can trigger the false damaged-app warning.

Download the Mac DMG from the official section.

Return to the homepage download panel, download the universal DMG, then follow this page if macOS shows the warning.

Go to Download