How to format a 16Gb CF card

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How to use Windows to reformat a 16Gb CF card back to 16Gb if you accidently formatted it to 8Gb with your camera

If you bought a 12 or 16Gb CF card and you camera only supports 8Gb (like the Canon 5D), you might have formatted the card with your camera, and now it only shows 8Gb. The Windows tools format or Disk Management are not able to fix this (to get it back to the original size). The solution is to use the command prompt and run the program "diskpart". Open the "run" command or a DOS prompt to run the program (Type DISKPART to start the program). The prompt will look like the image below:

Type: LIST DISK to show the disks on your system. The image below shows the prompt listing the disks on my system. Note that the 15Gb CF card formatted with the 5D only shows 8Gb in Windows, but list the card as 15Gb in this prompt (the disk size, not the partition size):

Type SELECT DISK 1 to select the CF card (type the number for the CF card that shows up in your system). The prompt will show: "Disk 1 is now the selected disk.". To be sure you have selected the correct disk, type LIST DISK again. The selected disk should now have a star next to it as in the image below:

To select the 8Gb partition, type LIST PARTITION to see that the selected disk is the 8Gb disk. Type SELECT PARTITION 1 (in this case) and the prompt should look like below:

You may type LIST PARTITION again to be sure the selected partition has a star next to it to show it's selected.

To continue from here, you have to be absolutely sure you know what you are doing. It's very easy to delete your main disk if you are not sure where your are!!!

To delete the 8Gb partition, type CLEAN and press Enter to delete it. This is all it takes to delete the disk, so be very careful!

Type EXIT to leave the Diskpart program and continue in Windows Disk Management.

Open Windows Disk Management, rightclick the disk for the CF card and select "New simple volume" (as in the image below), and the default new size shold be 16Gb (or 15631Mb in this case for a Sandisk Extreme III 16Gb card). Follow the wizard and select FAT32 as file system and "Quick format" when prompted. It takes a long time to format the drive if you do not select the "Quick format" option. With Quick format it takes only about 10 second to format the card to 16Gb. Job done...

A soon as you put you card in the camera (in this case the Canon 5D), the camera will make the folders as normal and you may use the full capacity of the card again.

Another option is if you know anybody having a camera that supports CF cards larger than 8Gb and ask them to format the card for you. A lot easier and a lot safer!

It might seems like a lot of work to change the partition size on this card, but actually it's just a few steps:

* DISKPART
* LIST DISK
* SELECT DISK
* LIST PARTITION
* SELECT PARTITION
* CLEAN
* and then do the new formatting.

...but it's very important to know what you are doing, especially if you are not used to the command prompt (black screen). Don't blame me if you delete one of your main disks. I take no resposibility if you delete your disk, but the info on this page is as close as possible to solve this problem.

I have doublechecked the info on this page, but if you find any errors, I would appreciate it very much if you send me a mail regarding this.

Last updated 05.03.2008