Raid 1 Problem D Drive filling up

Hello everyone and thank you for looking at my problem. In a Raid 1 the 2nd drive(D) shows it is filling up. I cannot read any files on the D drive. I know on a Passport external there was a folder to open so the drive can be read. This began when win7 updated to win10. I know there are backups and updates that I should be able to delete but I need to be able to read drive D. This PC is 5 hours away and I am tying to help my friend. Is this just an issue where I can just hide the drive and ignore?
Thanks for any help you can give me!

Help please.