Converts an empty basic disk with the master boot record (MBR) partition style into a basic disk with the GUID partition ...

    Converts an empty basic disk with the master boot record (MBR) partition
    style into a basic disk with the GUID partition table (GPT) partition
    style.

Syntax:  CONVERT GPT [NOERR]

    NOERR       For scripting only. When an error is encountered, DiskPart
                continues to process commands as if the error did not occur.
                Without the NOERR parameter, an error causes DiskPart to exit
                with an error code.

    A basic MBR disk must be selected for this operation to succeed. 
    
    The required minimum disk size for conversion to GPT is 128MB.
    
    Important:

        The disk must be empty to convert it to a GPT disk. Back up your data,
        and then delete all partitions or volumes before converting the disk.

Example:

    CONVERT GPT