Which "drive" to I back up?

I’m getting ready to update to the latest version of HA and I typically use Win32 Disk Imager to make an image of the SD from my RPi before doing so. Usually, when I put the card in my Windows machine, I see a single drive. Today, I’m seeing 4: RECOVERY (E:), boot (G:), and 2 drives with unreadable file systems (F: & H:). Is there an easy way to tell which is the correct one to back up? I’m currently reading F: and it’s taking a while, so it seems like I’ve got the correct one. Is there an easy way (from a Windows machine) to tell that I’ve got a good backup?

Note: AIO install on Raspian Jessie