Keychain is a password management system for Mac. Dropbox requires access to your Keychain to help verify your account and to provide another layer of security over the Dropbox desktop app preferences.

• To grant Keychain access to Dropbox, click Allow or Always Allow when prompted. Always Allow is recommended for seamless access.
• Clicking Deny will result in a "Couldn't start Dropbox" error message. For security reasons, Dropbox will not start without access to your Keychain.

Dropbox Web Helper supports the Dropbox user interface on Mac computers. It only runs when the desktop app is running.

Dropbox Web Helper is an independent process, so it may start and stop at different times than the desktop app. If you adjust your firewall or antivirus software for Dropbox, we recommend similar adjustments for Dropbox Web Helper.

The Dropbox system extension is automatically installed when you install the Dropbox desktop app. It allows you to open online-only files from File Explorer (Windows), Finder (Mac), or third-party applications.

Notes:

• The Dropbox system extension doesn’t apply to macOS 11 or later.
• If you’re on a Dropbox team account, an admin on your team can restrict your ability to install or uninstall the system extension.
• Installation of the Dropbox system extension is not applicable to macOS 11 or later.
  • If you're having issues opening online-only files on macOS 12.3 and above, you can open them directly in Finder.
• If you’re on macOS 10.15 or earlier and experiencing issues installing the Dropbox system extension, you may need to update your system preferences to allow the blocked system extension. Learn how to update your system preferences.

If you’re on Windows, macOS 11 or earlier, or Linux, and you’re having issues opening online-only files in the Dropbox desktop app, you may be missing the Dropbox system extension.

To reinstall the Dropbox system extension:

1. Log in to dropbox.com.
2. Click your avatar (profile picture or initials) in the bottom-left corner.
3. Click Settings.
4. Click the General tab.
5. Make sure the toggle Dropbox system extension is set to On.
6. Uninstall and reinstall the Dropbox desktop app.