When you connect a disk larger than 2TB on your computer, the hard drive only shows 2TB in Disk Management and the option New Simple Volume is grayed out. While creating a new partition on a large disk with third party software, you may receive a message that the disk space beyond 2 TB will be unusable or something like that.
There are two different partition styles, one is MBR (Master Boot Record), and the other is GPT (GUID Partition Table). While you initialize a hard drive, Windows will ask you to choose the partition style. An MBR disk supports maximum volume for 2 TB (Terabytes) and holds at most 4 primary partitions. Therefore, you can't create new volume on unallocated space beyond 2 TB on an MBR disk. However, GPT disk partition style supports maximum volume for 18 EB (Exabytes) and the limitation for partition size depends on your operating system (Windows allows up to 128 partitions on a GPT disk. Since the problem is caused by the limitations of the partition style, you can convert MBR disk to GPT disk to solve it.
Solution 1: convert to GPT with Disk Management
Windows has its built-in partition tool Disk Management that can convert a blank MBR disk (shown as unallocated space) to GPT disk. To do this, you have to delete all the volumes. It is recommended to backup disk before the conversion.
1. Open Disk Management. Then right click the partition on the disk your want to covert and select Delete Volume.
2. You can see the whole disk shown as two separate unallocated spaces. Right click the disk and select Convert to GPT disk.
3. After the conversion, you will be able to use the whole disk.
Solution 2: convert to GPT without data loss
If you want to convert to GPT disk without losing data, you can use third party software AOMEI Partition Assistant. It is available for both PC and Server users in many different versions. It supports Windows 10/8.1/8/7/XP/Vista and Windows Server 2012/2008R2/2008/2003. If you want to convert the non-system disk, you can free download the Standard version for PC or Lite version for Windows Server. If you want to convert system disk to GPT, you need to purchase the Professional version for PC or Server version for Windows Server.
1. Install and launch AOMEI Partition Assistant.
2. Right click the disk and select Convert to GPT disk.
3. Click Apply to run the operation. Then you are able to create a new partition with the unallocated space.
Note: if you want to convert system disk to GPT disk, make sure your motherboard support UEFI Boot Mode, and enable UEFI boot mode after the conversion. The Standard (free) edition is able to convert non-system disk to GPT disk without data loss. For system disk, you can try AOMEI Partition Assistant Professional for PC or AOMEI Partition Assistant Server for server.
Having solved the problem that the disk space beyond 2tb will be unusable, AOMEI Partition Assistant can also be useful to many other matters as it provides multiple features, such as Migrate OS to SSD, Disk Copy, NTFS to FAT32 Converter, Windows to Go Creator, and more.