I run the following command:
rsync -rvtO --delete myUser@myHost:/backup/\* /backup/folder/
It copies the files from the source host, but does not delete files in the destination folder that no longer exist on the source. I get no error message. This rsync version is 3.0.4 protocol version 30. The --delete option on other computers just fine. the rsync user does have permission in the /backup/folder directory because I was able to delete a file in that directory by-hand logged in as the rsync user. The /backup directory is a mounted external USB drive.