Raspberry Pi SD cards are notorious for being corrupted and having to be reformatted, taking everything you’ve worked on with them. It is common sense and good practice to always backup your card whenever you make progress on a project. In case anything happens, you can just reload the image onto the SD card and it will be as if there never was a problem.
Thankfully, backing up an SD card is a very simple task, and can be done in only a few minutes. Not only that, the same procrss can be used to create backups of USB drives and, more uncommonly, hard drives.
The program is super-simple and intuitive. Download the .zip from the Sourceforge link above, extract it, run the application, and you’ll see this:
Creating a backup: Change the device dropdown to the drive with the MicroSD card you want to copy, and specify where you want to save the “Image File”; hit that little pictogram file to browse and find a name and location for it. Hit “Read”. This will take your card and produce an image file in the specified location of everything on it.
Please note: Before we go on, I did have an issue once where the program could not locate the image file it had just made. When I looked in the folder with Windows Explorer there was a generic FILE with the name I had given it of the correct size. Close Win32 Disk Imager and put .img at the end of the FILE name. This will convert the unspecified file into an image file. Rerun the program and it will recognize this and it will work.
Putting the Backup onto an MicroSD card: Now that you have the image file “read” from the card, putting it back onto a card, for whatever reason, is just as simple but in reverse. Locate the image of the card you would like to use with the little file pictogram again. Then, choose the drive with the card you want to put the backed up files on with the device pulldown. This time click “Write”, it will prompt you to let you know that this will delete everything on the drive. If you are sure you have the right drive, click OK and it will go and put the backup copy back onto the device.
Another note: This will be a complete replica of everything that had been backed up before. When you use the card now, it will be exactly like the time you backed it up. Another important point is that when you are using 2 separate sized SD cards, you can backup a smaller size onto a larger one, but not vice-versa. For example, we put an 8 GB image onto a 16 GB card. The thing is, that new OS in the 16 GB card still thinks it is in an 8 GB drive, as it is a complete copy. That image is the extent of its universe, so to speak, and the free space on the 16 GB card is simply unknown to it. Keep this in mind, and try to invest in microSD cards of the same size. (Unlike we did.) Theoretically, there might be a way to have a sort of dual-boot device, but we haven’t tried or done any research on that yet.
Windows 8 Users
I was unable to use Win 32 Disk Imager on my Windows 8 device, many of you have faced the same problem.
You can download Roadkil’s DiskImage and it works on Windows 8! There are 2 tabs at the top instead of the Read and Write buttons you have Write Image and Store Image. Store Image will create the backup, Write Image will put it on the card.
Important note: Write Image did not work for us at first, “Error #5 occurred while writing to disk at sector 2048”, but the fix is easy. According to the developer Roadkil, “Its due to a locking problem on the logical partitions on the physical disk”, he promised an update with a fix in the future (we used 1.6) but there is a simpler fix, in the meantime. Just reformat the SD card again to wipe the partitions, then write the image to it.