Lost password on 4Tb passport for Mac

I’ve had a 4TB passport for Mac about 6 months.It is password protected, and normally the password box appears when I launch the drive on my iMac,I input the password and the drive launches on my desktop.No problems until yesterdayNow,when I plug the drive into the iMac,there is no password prompt box,and the drive immediately opens on my desktop and is ready to go.So I have no security on my drive and any one can launch and open it.Where did my password go,and how do I reinstate it.

Hi,

You could refer to the following link: https://support-en.wd.com/app/answers/detail/a_id/20555