If you want to use it as a data drive, it won't have a System Reserved.
All you'd need to do is format it.
What happens when you try to format it to full capacity?
You would need to initialize the drive as GPT rather than MBR if the drive is larger than about 2.2 TB and you want to see and use the entire capacity.
Disc 1 1TB to use has data disc, management states unallocated partition is a dynamic disc
can't delete and expand to full capacity.
The unallocated portion of Disc 1 is NOT a partition. Ignore it for the time being.
Is there anything you care about at all on Disc 1?
If not, you should be able to delete partition E on Disc 1 by highlighting it and right clicking.
That should leave you with 100 percent unallocated space on Disc 1.
You should then be able to reformat Disc 1, but do NOT, I say do NOT say yes to dynamic disks. They are very rarely anything you'd need and are to be avoided whenever possible.
You would want it to be a "basic" disk, like all the others.
If there IS something on Disc 1 that you want to keep, you would have to copy whatever that is to some other disk before deleting any partitions on Disc 1. But I assume it has nothing you want to keep since you are trying to format the drive.
If you want to convert your drive from dynamic to basic without losing data follow Option One:
Convert a Dynamic Disk to a Basic Disk
Problem solved using ignatzatsonic's advice thanks everyone for advice.
For others facing the same problem you don't need to lose your data. Follow Brink's tutorial in the link above.
Quote