Trying to backup sd RasPi card, says to reformat

Just purchased RasPi preloaded 16GB MicroSD card with NOOBS for Raspberry Pi 3 model B+ from Core. I have gone through the process of updating and …now trying to produce a backup copy.

I downloaded win32imager onto my Windows 10 desktop computer… I inserted the RasPi MicroSD card and then clicking on the blue folder of win32imager, which results in the message of "You need to format the disk in drive D: before you can use it. Do you want to format it? [format disk] [Cancel].

Can you advise an alternative/correct way to backup as the above seems as if will lead to wiping the MicroSD card.

Thank you.

My experience is that once an SD has been installed with Raspbian on a Pi, the formatting that Linux applies, when it is initially run, is not compatible with windows. Making a duplicate SD card would have to be done on a Linux system.
Rather than making a duplicate, I document the process I go through creating a project so I can easily setup the software again; if needed. Any files I create on the Pi I backup to windows using FireZilla SSH FTP.


Sounds like you have the sequence wrong (specifically, you are instructing Win32 Disk Manager to create the backoup “on” your uSD card):

  • Insert the card first
  • Then open win32imager (otherwise, the uSD won’t be in the device list)
  • In the “Image File” box, choose the destination for the image file (eg on your desktop, give it a name like I did below)
  • Select the device drive for the uSD card
  • Click on read
  • If you like, rename the completed image file with the extension .img so that it naturally opens in other image software


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The windows is objecting to the Linux Partition format. You will see you have 2 drives appear when you insert your SD card. One is Windows machine readable Boot and the other which windows wants to format is a linux parition. The linux partion can be read using these 3rd party tools.

If you are using your Imager to back it up … just ignore the format request as you dont need to be able to read it to make an image of it!!! Imager will make a complete image of the SD card including the 2 partitions (I think!).

[edit] If you listen to windows and format the Linux partition … I hope you can guess that stuffs it :>

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Hi James, Thank you for your prompt response and advice.

Hi Graham,
Thank you for the detailed instructions.

It seemed somewhat contrary to what I would expect it, so thank you…but I’m still concerned.

I have 2 questions if you would please consider.

Question 1

Directly below, I’ve identified a file path for the Image file and I’ve selected E: drive as the location of the uSD card.

I get the response directly below, which I don’t wish to choose Yes, as it seems incorrect?

I have no files in F:/RasPiBackup, yet Win32 requests that I overwrite the specified file? Seems odd.


Question 2

The other quandary I have is… I insert the uSD in my card reader and the result is 6 drives, ie 3 additional drives from one uSD card.

Prior to uSD card in the reader, 3 drives, C & F, with the card reader shown as H, but greyed out.

Inserting the uSD, I now have 6 drives.

E & H drive seem to have rpi file, with E drive being the most relevant.

USB Drive G cannot be read and requests to be formatted.

Thank you for your consideration.


Hi Peter,
Thank you for the link.

I’ve just seen your comments and you were correct in the additional 2 drives…

I’m not happy at the moment to push the button on Win32 image writer, given my notes below.

Clicking the verify says the selected file does not exist.

I think I’d better read your links, Win32 Disk imager, just seems contrary to what I expect.

Thank you for any future advice, appreciate your comments.


Before inserting uSD card, 3 drives, C: & F: with my card reader greyed out and shown as H


After inserting uSD card into reader, 6 drives. E & H have Raspi files, where as clicking on G and D brings up the dialog box to reformat them.

Clicking the verify shows the following error, so not going to click the write button.


@Charles78749 try adding a file extension to your backup file.


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Hi Charles,

I have been playing with Win32 Disk Imager after my previous comment.
I am happy that it will back up my Pi SD cards, which is a much better option than tying to duplicate a documented process.

I note on both your screen shots Read Write & Verify Only are enabled.
This only occurs for me when the file I want to backup to already exists.
Check that the file has not already been created, or try a different name as suggested by Arnold.
It is always good to use the file extension so the system knows what type of file it is.

Or you have typed the name and it is pointing to a directory, I tried this and it produces the same error.
If you click on the folder icon to the right it makes you specify a name.

Thanks for your post it has helped me in my adventure, Cheers

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Hi James,

Its worth mentioning that every Pi comes with a SD card copier installed on it that will quickly and easily copy the image on the Pi to another card. All you need is an SD card reader, you can find the copier under “Accessories”


+1 for the copier mentioned by @Stephen Have used it myself often enough and works well. Of course doesn’t work if you are wanting to store the image as a file for later use.

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Hi Arnold,
I’m looking into Stephen’s option of the SD card copier under “Accessories”, which I explore in a moment.

You mention…*Of course doesn’t work if you are wanting to store the image as a file for later use. *

Can you explain this…as the purpose of the backup for me will be when the card corrupts and I wish to get a copy to run on my RasPi.

Some history and my present status. Last week I downloaded a file and it corrupted my RasPi SD card, so I thought I’ll grab a preformatted SD card with the OS from Core.

Today I’ve been experimenting with Win32 Disk Imager. I’ve successfully loaded an image file onto my windows machine, all good.

Now I wish to copy the image to my corrupted SD card which has been reformatted. I bailed out as the risk of me stuffing up was high, so I reverted to creating a new RasPi Raspbian OS on my old SD card, which seems to be going well. All good learning experience and just pleased to see so many willing to assist me. I’m truly amazed at the positive and helpful contributions from the community and Core, most impressive.

Regards Charlie

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Arnold, that was helpful, got the image to copy to the Windows machine. Thanks

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Hi Stephen,
Thanks the note to Arnold about the SD card copier, that is interesting, I explore in a moment. Thanks for the tip.

Charles, I just meant that the copier that is referred to is great for coping an image from on SD card directly to another SD card. I know in my case that i wanted to take an image of the SD card and store it for later use. I didn’t want to keep an actual physical SD card with my image on it.

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Hi Arnold, Brillant, thanks for clearing it up for me, have a good weekend.


Well this was an excellent topic and timely to what I have been doing.

The SD copy command in Accessories is useful to make another bootable SD card, the same as the one you are currently using. But not if you want to archive the SD image. Running from the GUI means you need to have that working also.

Win32 Disk Imager makes an image of the SD card, that can be saved or moved just like a file. But it is the same size as the total size of the SD card. ie an installation that uses 3GB on a 16GB card the file will be 16GB.

PiShrink solves that issue very nicely but will only run on Linux system. (Ubuntu on an old PC worked good for me) Other sites mention Virtual Box running Raspberry Pi, but that doesn’t work for me, yet. But overall an interesting topic.

Thanks Charlie for your post, it has greatly enhanced what I do and my understanding. Cheers


Hi James,
Now I understand why my Win32 image file that I saved on my Windows 10 PC came from a 16GB would not save to an 8GB SD card. Makes sense now, brilliant work.

So…SD copy command in Accessories for a bootable SD card and use PC Shrink for more than a bootable copy via a Virtual Linux system, which I’ve done before on my PC.

Thank you for your insightful comments and efforts. Thanks James have a good weekend, Regards Charlie

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