After you uninstall Backup and Sync, you can still find your files at drive.google.com. Open Finder and click Applications. Drag the “Backup and Sync” app into the Trash on your dock. In the top left of your screen, click Finder Empty Trash.
https://support.google.com/drive/answer/2375081?co=GENIE.Platform%3DDesktop&hl=en