Deleting SD-Card partitions under windows 7

This post was written by Tobias Kern on March 21, 2013

After playing around with RaspBMC on a Raspberry Pi I wanted to reuse the SD-card for a different project. Unfortunately after inserting the card into a windows PC only the first partition on the card did show up in the windows explorer reducing the capacity of my 32GB card to about 64MB. “No problem” I thought and tried to delete all the partitions in the Windows Disk Manager which turned out not to be as easy as I thought…

More after the break

First things first: Sorry folks, but the command prompt responses and the pictures are in German, since I use a German version of windows. But the Instructions should be easy to follow anyway…

As I mentioned, Windows told me my 32GB card only had 56MB as you can see in the following picture

Windows shows the SD-Card too small

This picture shows the SD-Card capacity windows displays in the Explorer, which is way too small, only about 56MB

So i fired up the windows disk manager to find out what was going on. As you can See in the picture below the card had been split into three partitions. So by deleting all the partitions and afterwards creating a new big one I wanted to restore the full card capacity. Deleting the last two partitions was fairly easy: right click on them and select “Delete Partition” from the context menu…

dialog to delete a volume under windows

This pic shows the windows dialog to delete a volume, as you can see the option is not greyed out

But for the first partition this option was greyed out:

The option to delete volume is greyed out

This picture shows the windows dialog to delete a volume, as you can see the option is greyed out this time

But fortunately there is the good old command prompt. In this case the tool DISKPART was the solution to the problem. After opening a command prompt just type in DISKPART. Since this program needs administrative rights windows asks us if we really want to procede. After agreeing another window opens and the prompt now looks like this: DISKPART>

the following command lists us all the available disks:

DISKPART> list disk

Datenträger ### Status Größe Frei Dyn GPT
————— ————- ——- ——- — —
Datenträger 0 Online 238 GB 0 B
Datenträger 1 Online 931 GB 931 GB
Datenträger 2 Online 29 GB 0 B

DISKPART>

We know our SD-Card has a size of 32GB so we can see it must be “Datenträger 2” which we now select with the following command:

DISKPART>select disk 2
Datenträger 2 ist jetzt der gewählte Datenträger.
DISKPART>

Now we can just delete all partitions on the selected disk by using the clean command:

DISKPART> clean
Der Datenträger wurde bereinigt.
DISKPART>

After that you can check your disk manager again and we will see a completely uninitialized SD-Card that we can now format using FAT32… Hope this halps you as much as it helped me. Cheers, Tobi

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