I have installed Ubuntu 12.04 on my D: drive, alongside by Windows 7 installation on my C: drive. However, now when I boot into Windows 7, my D: drive is missing.
How can I get my D: drive to reappear in Windows 7?
When I boot into Ubuntu, all drives are visible.
You installed Ubuntu on the former Drive D: in Windows. So, it is used by Ubuntu and now has a EXT4 filesystem. As Windows can't show ext4 partition, you can't see that drive.
You can still see that drive by going to the "Disk management" in Windows. That partition should have label "unknown".
To run Disk management, press Start menu and type diskmgmt.msc and Press and hold Shift key and then hit Enter.
Ubuntu uses the ext4 file system which is a file system that Windows cannot see. When you boot into Ubuntu you can see your C: drive because it's formatted as NTFS, which Ubuntu (Linux) can recognize. Windows however cannot see, mount, or access an ext4 file system.
So, if you want to share files between the two installations, just keep all your stuff on your Windows installation and access them from your Ubuntu installation, since you can't do it the other way around.
True is, you cannot access ext4 filesystem/partition by windows OS. my solution is to reduce ubuntu partitions and create ntfs partition which will be shared among all the operating systems. after creating the parititon you can assign drive letter in windows and create a mountpoint in linux (directory which will be pointed to this partition).
use gparted to shrink ext4 partitions or diskmgmt.msc to shrink ntfs partitions (although gparted can handle NTFS partitions, diskmgmt is safer).
(to install it - sudo apt-get install gparted)
DO NOT change or move "System Reserved" partition (a 100MB partition, the first one) because it will ruin your boot process.
also, DO NOT move the partition which holds "/boot" mountpoint (if you chose the default, it's the "/" mountpoint. GRUB might be corrupted after.
