I am assuming that you are referring to the Password option offered in Acronis when making a Full Backup - if so, make another Full Backup but when asked if you want to enter a Password, leave it BLANK. Delete any earlier Full Backups and Incrementals etc.
Technotiger Until I see for myself it seems that a partition (D:) set aside for backups, has a password set preventing access to the drive contents. The password is known but its presence is unnecessary and inconvenient.
Can it be removed in Disk Manager or some other built in feature?