Unexpected, Huge 3rd Partition, Apparently Unformatted

I backed up an image of my old hard drive onto a mass storage device, and then restored that image to my new 1 TB hard drive.

The new drive came unformatted, so I formatted it before restoring the image to it, although I later learned from Macrium Reflect, my disk imaging app, that I hadn’t needed to do that.

Anyway, here’s a screenshot from Macrium Reflect showing the new hard drive.

I had expected the Windows10_OS partition to fill up the remainder of the disk left over from the SYSTEM_DRV partition.

But instead I’ve got this huge 475 GB 3rd partition, apparently unformatted.

But I want to be able to use the WHOLE disk.

Did I screw up when formatting the dirk? Or is Windows using this space for something?

What should I do?

 

Maybe this mystery partition is for restore points?

 

It isn't a partition, it's just unused space. Use Disk Management to extend the Windows partition. You could also have done that in Macrium.

 

Wow, that was easy! I used Disk Management. Thanks a lot!