First for installing the windows operating system in Apple Macbooks, we must convert the partitioning scheme from GPT(GUID Partition Table) to MBR(Master Boot Record). The conversion can be carried out by the tool gdisk. The documentation they have provided is well written for the particular operation. Now let’s discuss, why do?

What is the advantage of GPT disk?

GPT disks can grow to a very large size. Break the 2TB limit of MBR disk. GPT disks allow an almost unlimited number of partitions. Each GPT partition has a unique identification GUID and a partition content type. And you can have more primary partitions. However, the Windows implementation restricts this to 128 partitions. Another purpose of mine is that, I wanted to resize and modify the partition with the Disk Utility tool but the options are disabled because my disk was in MBR partition.

How to change MBR to GPT

I ended up using gdisk to convert the partition. I issued:

  sudo gdisk /dev/disk0

And you might be greeted with this warning:

  Partition table scan:
  MBR: MBR only
  BSD: not present
  APM: not present
  GPT: not present

  Found invalid GPT and valid MBR; converting MBR to GPT format.
  you don't want to convert your MBR partitions to GPT format!

  Command (? for help):

After backing up my data, I wrote the partition table with the changes gdisk made automatically, quit (w, then q), and rebooted. Booting may be normal, but when you will try to resize the partition table with Disk Utility, you may get a minor volume header error.

  Verifying volume "Mac OS X"
  Performing live verification.
  Checking Journaled HFS Plus Volume.
  Checking catalog file.
  Checking multi-linked files.
  Checking extended attributes file.
  Incorrect number of extended attributes
  (It should be 245871 instead of 245862)
  Checking volume bitmap.
  Checking volume information.
  The volume Mac OS X was found to be corrupt and needs to be repaird
  Error: This disk needs to be repaired...then use Disk Utility to repair this disk

Then reboot and used -s to boot into single user mode. From there, use following command string -

  /sbin/fsck -fy

Now all is well. Eh!! have problems, can be posted in comments.