You can convert disks only from MBR to GPT, or vice versa, if the disk does not contain parti-tions or volumes. You can convert a disk in two ways:

• In the Disk Management snap-in, right-click the MBR drive you want to convert to GPT and then click Convert To GPT Disk. If the drive is not empty or contains partitions, this option is unavailable.
• In the DiskPart command-line tool, select the drive you want to convert and run the command convert gpt. Similarly, to convert from GPT to MBR, run the command convert mbr.