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How do I repartition an SDHC card (4 GB or more)? Do I need third-part tools or Linux (a live CD solution would be OK)?

In Windows' Disk Management the option Delete Partition is dimmed out:

Enter image description here

I can reformat the card as FAT32, copy files to and from the card and even change the file system to NTFS using the command line command CONVERT, but not repartition it.

The article How to Partition an SD Card in Windows XP talks about using "a Windows enabler program" which sound rather dubious to me.

I have tried to change from “Optimize for quick removal” to “Optimize for performance”. The option to format as NTFS appeared, but the Delete Partition option is still dimmed out.

Platform:

I have also tried on different versions of Windows and with different cards with the same result:

  • Kingston 4 GB SDHC card, speed class 4 (the one shown in the screenshot)
  • Transcend 2 GB (not marked as SDHC, but SD)
  • Windows 7 32-bit (albeit with a somewhat an older card reader) and Windows XP 32-bit on an EliteBook 8730w
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Why do you want to partition the SD cards? –  James Oct 10 '12 at 9:13
2  
It is a limitation of Windows that only the first partition of a removable disk can be mounted. (USB HDDs report themselves as fixed disks.) While it is possible to format a removable disk with multiple partition using a third party tool, you would not be able to mount anything beyond the first partition. This is not SD card specific, but SD cards are typically considered removable disks (unless you change the driver). –  Bob Oct 10 '12 at 9:24
    
James: I want to shrink the partition size in order to be able to format as FAT16 (FAT32). This is to do some testing on an embedded device that currently has reliability problems writing to an SDHC card. It may even turn out to be a work-around for the current problem. –  Peter Mortensen Oct 10 '12 at 13:40
    
@PeterMortensen: There is a similar question here with a solution: superuser.com/a/202236/13459 - using the diskpart command-line tool in Windows you can clear the partition table and create a new partition under 2GB that can then be formatted as FAT16. However, please be careful to select the correct 'disk' so that you do not wipe the wrong drive. –  James Oct 10 '12 at 15:42
    
@PeterMortensen: did you have any luck? –  James Oct 12 '12 at 12:15

3 Answers 3

You can delete it with the DiskPart command line tool on windows. Read this http://www.winability.com/delete-protected-efi-disk-partition/

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Link seems to be broken. Adding the actual command would be very helpful. –  bvukelic Dec 4 at 14:25

Here's an article with working link. And also a summary of how you do this:

Start DiskPart by opening Start menu and typing in diskpart in the search. After giving DiskPart permission to start with administrative privileges, you will be in a console window with DISKPART> prompt.

Deleting partitions

Type LIST DISK to find out what disk you need to change. Note that you are looking for a disk with the same number as in the Disk Management tool, so in OP's case, it's Disk 1.

Next you need to select the disk you wish to work on. Type SELECT DISK 1. Make sure the correct disk is selected by typing LIST DISK again.

Now, you need to select the partition you wish to remove. Type LIST PARTITION to see a list of all partitions. To select the first one, type SELECT PARTITION 1.

To remove the partition, type DELETE PARTITION.

Creating partitions

To create a partition, you can either proceed by using the Disk Management tool, or type CREATE PARTITION PRIMARY. This creates a partition that fills the free space. If you wish to create a partition of specific size, you need to type CREATE PARTITION PRIMARY SIZE=NNN where NNN is the partition size in MB.

You can get more information about the various options by typing HELP CREATE PARTITION and/or HELP CREATE PARTITION PRIMARY.

Exiting DiskPart

Either type EXIT or press Ctrl+C.

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You can't delete a partition while it contains a filesystem that is currently set to be always mounted. Remove the drive letter (From the Change Drive Letter and Paths option) and then you should be able to delete the partition.

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On one of the computers, I removed the drive letter and tried with "Optimize for quick removal" and with "Optimize for performance" (though the NTFS formatting option did not appear for some reason for the "Optimize for performance" option). I also restarted the computer. The option is still dimmed. I will try it on another computer/setup later today. –  Peter Mortensen Oct 10 '12 at 14:19

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