[macOS] If you cannot delete a DataVaults file, try this…

1. Reboot into recovery mode (⌘-R as soon as you hear the startup chime)
2. Use the menu to open Terminal
3. Type "csrutil disable" + return
4. Then reboot
5. Now empty the trash.
6. Finally, re-enable SIP by booting back into recovery mode and using the command "csrutil enable".
7. Reboot and you are good to go.

Source: https://forums.macrumors.com/threads/cannot-delete-item-in-trash.2182377/?post=27690767#post-27690767