Unable to extend MBR Disk beyond 2TB

Products

• VMware vCenter Server

Issue/Introduction

Unable to extend the disk within Windows guest OS beyond 2 TB since the extend option is greyed out.

 

Environment

Windows Server 2000, 2003, 2008, 2012, 2016, 2019, and 2022

Cause

MBR supports a maximum partition size of approximately 2.2 TB due to its 32-bit addressing limit, which restricts the maximum addressable sectors. Therefore, any partition on an MBR disk cannot be extended beyond this limit.

Resolution

Kindly, engage Windows Guest OS Administrator or OS Vendor to perform below steps. 

• Create a new virtual disk and initialize it using the GPT (GUID Partition Table) partitioning scheme. Then, copy all data from the current (e.g. D: drive which resides on the MBR disk) to the new GPT disk. After verifying the data transfer, remove the MBR disk and, if necessary, reassign the drive letter to maintain consistency.
• If the disk is a boot disk, ensure that the system firmware supports UEFI mode, as GPT boot disks require UEFI instead of legacy BIOS for proper booting. Format the partitions on the new disk using NTFS, which supports large volumes and files, allowing you to fully utilize GPT's capabilities.
• Before performing any conversion or data transfer, back up all important data to prevent loss, especially since some conversion methods may require deleting existing partitions. Tools like Microsoft’s MBR2GPT.exe can help convert disks from MBR to GPT without data loss, but a backup is always recommended as a precaution.

Refer https://learn.microsoft.com/en-us/windows/deployment/mbr-to-gpt