Convert MBR to GPT without Data Loss
MBR caps at 2 TB per disk and four primary partitions; GPT lifts both ceilings (9.4 ZB, 128 primary partitions). For data disks on a running Windows Server, the right tool is DiskGenius - free, online, three clicks per disk, no data movement, no reboot. This article walks the workflow: identify MBR disks with Get-Disk, convert with DiskGenius (right-click - Convert To GUID Partition Table - Save All - Yes), repeat for each disk, verify with Get-Disk, restart the server when the maintenance window allows. Includes why mbr2gpt.exe is the wrong tool for data disks (it is system-disk-only and requires WinPE), the gotchas (skipping Save All, converting from the wrong DAG node, BIOS-only servers and the system-disk constraint), and the difference between the in-place metadata-only conversion DiskGenius does and the copy-everything-over fresh-GPT-disk migration Microsoft suggests.
