Windows Disk Management can only extend a partition into adjacent unallocated space on the right. The 524 MB Recovery partition is blocking C: from seeing the 196 GB.

Option 1: Move the Recovery Partition (Safest)

Use a partition manager such as:

Steps:

  1. Move the 524 MB Recovery partition to the far right of the disk.
  2. Apply changes and reboot if prompted.
  3. Extend C: into the now-adjacent unallocated space.

Option 2: Delete and Recreate the Recovery Partition

If this is a server or VM and you're comfortable recreating WinRE:

  1. Open an elevated Command Prompt.
  2. Check WinRE status:
reagentc /info
  1. Disable WinRE:
reagentc /disable
  1. Delete the Recovery partition using DiskPart:
diskpart
list disk
select disk 0
list partition
select partition <recovery partition number>
delete partition override
exit
  1. Extend C: in Disk Management.
  2. Re-enable WinRE:
reagentc /enable

Before Deleting Anything

Run:

reagentc /info