I can't delete files and folders in trash sent from external hard drive used by Time Machine
I can't delete files and folders in trash sent from external hard drive used by Time Machine. I cleaned up my external Seagate Backup Plus drive by moving items I no longer needed to trash, When I try to empty the trash I get an error message: "The operation can’t be completed because the item “20080208” is in use." on every file and folder in the trash. When I eject the external drive from my iMac the deleted items in the trash disappear, however these items reappear once I remount the external drive. How can I delete these files once and for all?
iMac, OS X El Capitan (10.11.6)