Convert MBR Partition Table to GPT without Data Loss

The selected disk has an MBR partition table...

Sometimes, users would like to convert MBR disk to GPT for different purposes.  For example, when you install Windows 8, you may encounter an error that stated: "Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI system, Windows can only be installed to GPT disks." This could happen not only in Windows 8, but also in Windows 7, Windows 10, Windows 11, and Windows Server 2008, 2008 R2.

Meanwhile, you'll also need to make the conversion when you initialize a hard drive bigger than 2TB as MBR, or sometimes, you need more than 4 primary partitions on your hard drive in MBR.

About MBR and GPT

There're 2 kinds of partition tables, namely MBR and GPT.  MBR (Master Boot Record) is the old style of disks and is widely used by users. For MBR disks, you can create 4 primary partitions at most and the maximum size of each disk is 2 TB. In order to create more partitions, you have to build a structure with less than 3 primary partitions + one extended partition. Extended partitions are logical parts of hard disks, it can be used to create more logical partitions.

GPT (GUID Partition Table) is the latest disk style. It makes full use of globally unique identifiers to define the partition and it is a part of the UEFI standard. As for GPT disks, you are able to build unlimited partitions on the hard disk.

There are differences between MBR and GPT. Sometimes, in order to satisfy the various demands of the users. It is necessary to convert MBR disk to GPT.

Best Way to Convert MBR Partition Table to GPT without Data Loss

According to what you see at the beginning of the post, Windows can only be installed to GPT disks because of your EFI system. So the solution is to convert MBR to GPT? Yes, it is. But how to convert is a big question.

Of course, you can use Disk Management a built-in tool. But the disadvantage is that you may have to delete all partitions if there are partitions on your disk. And you need little technical stuff to be manipulated yourself. Following is Microsoft suggested solution: http://technet.microsoft.com/en-us/library/dn336946.aspx.

Besides, you can use Command Line to convert MBR to GPT. However, it is not data protective either and not every user is familiar with Command Line. So, if you don't want to delete all partitions and create partitions from the scratch and install the OS or using the complicated methods. Is there any simpler way to fix this problem?

Yes! I found a workaround to this problem. Without deleting all partitions you can achieve this. Just use a disk converter named an AOMEI Partition Assistant Professional Edition.

AOMEI Partition Assistant Pro is designed for Windows home users. With its powerful features such as allocating free space, converting dynamic disk to basic disk, migrating OS to SSD, making bootable CD, you can manage your partitions easily and safely. Furthermore, all of the functions can be supported by Windows 11, Windows 10, Windows 8.1, Windows 8, Windows 7, Vista, XP, 2000.

Step by Step Guide to convert MBR to GPT without Losing Data

Step 1. Install and run AOMEI Partition Assistant Professional. We can see the MBR disk from the main interface. Right-click it and select "Convert to GPT".

Step 2. Click "OK" and "Yes" in the pop-up windows.

Step 3. Now we can see the pending operations and click "Apply" to commit the changes.

Then we will say goodbye to "Windows cannot be installed to this disk. the selected disk has an MBR partition table. On EFI system, Windows can only be installed to GPT disks". Just 3 steps, we get rid of the irritating messages. So I think it is the simplest way.

Conclusion

With this powerful disk converter AOMEI Partition Assistant Professional, we can optimize our partition easily. Such as converting FAT/FAT 32 to NTFS, converting primary to logical partition, migrating OS to SDD and so on. We can even make a portable Windows 7/8/10/11 by using the function of "Windows To Go Creator". Meanwhile, if you want to use this software on Servers, please try the Server edition.