EC2 Instance showing a ghost volume

Hi, before doing anything else, I would try to understand where your "Unallocated Disk" comes from from WIndows stanpoint.

Have a look, for example, at https://7datarecovery.com/blog/unallocated-hard-drive/ to better understand what it can be and where it comes from. (it may just be unallocated space on 1 of your 3 disks)

When you know that , then use 'aws describe-instances --instances-id <your-instance-id>' (See https://awscli.amazonaws.com/v2/documentation/api/latest/reference/ec2/describe-instances.html) to obtain the list of EBS volumes attached to your instance.

With this pair of informations, you will be able to decide what to do with this unallocated space.

Hope it helps!

Didier