I tried installing Windows 10 IoT but now I want to come back to Raspbian stretch.

I mounted the sd card on my mac and tried to format the sd card to re-install the OS but my sd card became a 32MB card.

I tried to erase the card with GUI Diskutil but it wasn't working.

I've tried to format also with the terminal using this: sudo diskutil eraseDisk FAT32 EMPTY MBRFormat /dev/disk1 but stuck on 50% and it never ends.

I've downloaded SD Card Formatter but it throws these errors:

[ERROR] Invalid end of sector signature: 0x0000
[ERROR] fat_check_validate_boot_sector returned error: 22 (Invalid argument)
[ERROR] Initializing cached values failed: 22 (Invalid argument)
[ERROR] Generated invalid volume. fat_volume_create returned: 22 (Invalid argument)

I'm stuck and I don't know how to re-format this card to re-install Raspbian Strech


I'm using Etcher to burn the sd card and if I use it, it says the there is not enough space.

Update 2:

I don't think it's a duplicate of the question SD Card Showing as 30 MB on a 32 GB Card. Can't Format, Can't create a partition table as in that question, there are no error codes more he is working on Linux and not on OS X. Since I didn't tried with Linux and Windows I don't know if it is the same problem.


4 Answers 4


You can use "rufus" on Window to format your SD Card, it works with me :)

  • Unfortunately I'm on Mac Mar 20, 2018 at 4:58
  • 3
    You DO NOT need to format the Card to install an OS image.
    – Milliways
    Mar 20, 2018 at 6:58

I am using Disk Utility for Mac mostly, but sometimes it does not give exact results for me. So at that point, I am using a program called SDFormatter. You might want to try. SDFormatter

  • 1
    You DO NOT need to format the Card (on Mac or any other platform) to install an OS image.
    – Milliways
    Mar 20, 2018 at 6:57
  • I beleive you should make its format to FAT32. So dont you have to format it ?
    – HVK
    Mar 20, 2018 at 10:43
  • The card is broken! Apr 4, 2018 at 0:42

I've tried to format the micro SD card with an Android phone, with Windows, and with a camera. I can definitely say that the SD card is broken and no more recoverable.


Use SDFormatter, it is official from the SD Card enterprise, it is avaliabe for Mac and Win, i had the same problem and it worked for me.

An other way to do it in Mac is using Disk Utility (Disk utility on Mac page), it is already installed, go to Applications/Utilities/Disk Utility, it normally works. Don't forget to select exFat or FAT (MS-DOS)

  • NOTE: You Will need Admin Rights fot the Both Programs
    – yanko
    Apr 3, 2018 at 21:39

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