Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I have en external HD that I use with OS X. When I bought it, it was formatted for Windows (NTFS). I deleted the NTFS partition and created a new HFS+ partition. Then I copied 500 GB of material over.

Everything works fine when the external HD is directly connected to a Mac, but if I want to share the external HD by connecting it to a Time Capsule, I get an incorrect error message about the HD needing repair.

The problem is that the partition MAP is still in Windows format. For Time Capsule to recognize the disk, the partition map has to be in Guid Partition Table (GPT) format.

To do this, I have to delete the existing partition map. Will this also delete the underlying partition contents?

share|improve this question
    
Partition table formats are either MBR or GPT. There is no "Windows format." MBR is the older format which is still current an in use today, while GPT is the newer format that provides more flexibility and is where the industry is headed. –  Randolf Richardson Mar 7 '11 at 11:35
    
Older versions of Windows (before Vista SP1 maybe?) will not detect GPT and work with it correctly and that's the reason why windows uses MBR. It's possible to have MBR and GPT coexist fine,if the drive has less than 4 partitions, but I can't be bothered to look it up at the moment and provide detailed explenation. –  AndrejaKo Mar 7 '11 at 18:04
add comment

3 Answers

It's difficult to know for sure. Even if software promises not be destructive when changing the partition table, I still wouldn't take the chance without having a full backup of the drive first. Especially with a major operation such as change the partition table format, I'd worry that there's an even greater chance of data loss.

share|improve this answer
add comment

To do this, I have to delete the existing partition map.
Untrue. One can convert from the MBR partition table scheme to the EFI partition table scheme non-destructively using appropriate tools.

share|improve this answer
add comment

GUID is the new partition scheme and MBR is the old one

try to use this link http://support.microsoft.com/kb/282793

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.