VSS security relies on passwords that are stored with the data. Every user can have a password that allows access to VSS. There is no way to find out what a user's password is. If a user forgets his or her password, the VSS administrator can use this dialog box to assign a new password. You cannot recover an old password.
In many cases, you may want to change the password to something very simple, such as the username, and then instruct the user to create a new password from within VSS. Refer users to How to Change your Password for instructions on how to change their passwords.
As the administrator, you have a special password that is used to run VSS Administrator. You must enter the old password in order to change it. If you cannot remember the old password, contact Microsoft Technical Support.