Uninstall and reinstall the Dropbox desktop app.The window will change to a display of the contents of the external drive. It will be a drive letter, like E: or F: (unless you have changed it). Look for the Seagate External drive in (My) Computer/This PC. Make sure the toggle Dropbox system extension is set to On. Double-click to open (My) Computer/This PC.Click your avatar (profile picture or initials) in the upper right.To reinstall the Dropbox system extension: 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. Learn how to update your system preferences. 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.If you're having issues opening online-only files on macOS 12.3 and above, you can open them directly in Finder.Installation of the Dropbox system extension is not applicable 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.The Dropbox system extension doesn’t apply macOS 11 or later.It allows you to open online-only files from File Explorer (Windows), Finder (Mac), or third-party applications. The Dropbox system extension is automatically installed when you install the Dropbox desktop app.