When you receive the error message “Only the first 2 TB are usable on large MBR disks” while using Diskpart, this is related to the MBR max size limitation. This article will show you how to solve it.
Sometimes, when you use Diskpart to create or extend MBR partitions larger than 2 TB in Windows 11, 10, 8, 7, you may receive this error message: “Only the first 2 TB are usable on large MBR disks. Cannot create partitions beyond the 2 TB mark, nor convert the disk to dynamic.”
The reason why “Only the first 2 TB are usable on large MBR disks” is MBR maximum disk size is 2TB. MBR (Master Boot Record) disk can only be divided into 4 primary partitions or 3 primary partitions + 1 extended partition, and the disk size is up to 2 TB. It means that if you have a 5 TB MBR disk, then the part exceeding 2 TB will not be recognized by Windows.
Because of the MBR size limitation, if you want to use a hard disk larger than 2 TB, you need to convert the MBR partition style to GPT.
GPT (GUID Partition Table) was introduced as part of the Unified Extensible Firmware Interface (UEFI) project, it is used to replace MBR and can make up for the shortcomings of MBR. In other words, it supports hard drives larger than 2 TB. Recent year, GPT has gradually become the mainstream of the partition style, for example, you have to convert MBR to GPT for Windows 11 update if users want to upgrade Windows 10 to Windows 11 from "Check for updates".
Now, I will show you how to convert MBR to GPT with Diskpart. Before starting, you should know that Diskpart can only convert empty disks into GPT, which requires you to delete all partitions, so please make a backup before proceeding. You can follow the steps below:
Step 1. Press “Windows + R” and type in “diskpart” to open it.
Step 2. Type the following command line and press Enter in sequence.
● list disk ● select disk 1 (1 is the number of the disk which you plan to convert to GPT) ● clean ● convert gpt
After a while, you will find that the selected disk has been converted to GPT format. Type in “exit” to exit Diskpart. If successful, only unallocated space is on your disk, and the disk only can be used after creating some new volumes.
As you can see, although Diskpart can convert the disk to GPT partition style, you must delete all partitions. In order to avoid this situation to happen, we tried to find a way to achieve our goal without losing data.
You can try AOMEI Partition Assistant Professional (suitable for Windows 11/10/8/7), which is a professional MBR to GPT conversion tool. It is different from Diskpart in that it can directly convert a hard disk larger than 2 TB into GPT without deleting any partition, you don’t have to worry about data loss.
More importantly, it does not need to enter the complex command line, the whole process only needs to be clicked with the mouse and each step has very concise guidance, which is convenient for users who don’t have a computer background.
In addition, if you want to convert the file system of the hard drive from NTFS to FAT32 or convert the primary partition to a logical drive, it also can solve it for you. Please download the demo version for a free trial to see how it works.
Tip: If you plan to convert the system disk to GPT, you need to check if the motherboard supports EFI/UEFI boot mode.
Step 1. Install and run AOMEI Partition Assistant Professional. Click the disk (take Disk 2 as an example) and and choose "Convert to GPT" from the right column.
Step 2. Click “OK” to confirm your operation.
Step 3. Click “Apply” > "Proceed" to commit the pending operation.
After the operation is successful, the part exceeding 2 TB can be used, and you can use it to create a new partition or merge it with other partitions.
After reading this article, I believe you must have a clear understanding of how to solve the “Only the first 2 TB are usable on large MBR disks”. This article provides two methods for you to choose from, please choose one according to your actual situation. If you want to solve the “Only the first 2 TB are usable on large MBR disks in Server 2012/2016/2019/2022”, please try AOMEI Partition Assistant Server.
Why is there a 2TB limit on MBR disks? The 2TB limit on MBR disks is a result of the disk addressing method used by the MBR partitioning scheme. MBR utilizes 32-bit sector addressing, which imposes a maximum addressable storage capacity of 2^32 sectors, equivalent to 2TB when using 512-byte sectors. As a result, MBR disks cannot effectively manage storage capacities exceeding this limit.
What happens if I try to use more than 2TB on an MBR disk? If you attempt to utilize more than 2TB on an MBR disk, the excess storage space beyond the 2TB limit will be unrecognized and inaccessible by the operating system. This can lead to data loss, partitioning errors, or other storage-related issues. To fully utilize larger disk capacities, it's advisable to utilize GUID Partition Table (GPT) partitioning, which supports storage capacities exceeding 2TB.
How can I overcome the 2TB limit on MBR disks? To overcome the 2TB limit imposed by MBR disks, you can convert the disk to a GUID Partition Table (GPT) format. GPT partitioning utilizes 64-bit sector addressing, allowing for significantly larger storage capacities. By converting the disk to GPT, you can fully utilize the available storage space beyond 2TB without encountering the limitations of the MBR partitioning scheme.
Are there any drawbacks to converting MBR disks to GPT? While converting MBR disks to GPT enables the utilization of larger storage capacities, it's essential to note that the process is irreversible and may result in data loss if not performed correctly. Additionally, older operating systems and certain BIOS configurations may not fully support GPT disks, so it's crucial to ensure compatibility before proceeding with the conversion.