On my 2010 macbook I use TM to make backups of both my internal drives. All good no issues. But when I plug in the TM external drive it puts a folder in the bin. The folder is a backup file. inside is a file that appears to be a backup in progress file from 26th Jan 2017. I cannot delete said folder or contents. If I eject the TM drive then the file is gone from the bin. more annoyance than a problem but can I do anything?