Bitlocking of Physical memory drives started with Windows Vista and has been continued in Windows 7 however if we use the BitLocked drive on a Vista or XP machine we might face some problems. Problems like partitions on the drive would appear as FAT32 and all space would appear occupied. Users might see another small partition formatted as FAT 32 other than the one which has the data on it. This happens only if the media was encrypted using the BitLocker in windows 7 and now the drive is used on a Windows XP or Windows Vista machine. Now when you take this disk on other XP or Vista machine then the entire media would be displayed as using FAT32 and totally occupied. You would also not have any read/write access to the drive. If you connect such drive to a Digital camera, or an MP3 player then the device would not detect the drive at all.
This happens because when Windows 7 encrypts a drive using BitLocker it creates a discovery volume which is formatted in FAT32 file system in case of removable media. This discovery partition created by Windows 7 remains invisible in Windows 7 but gets visible in other operating systems. This discovery partition carries the BitLocking code which is an auto run application which allows the user to read and write to the encrypted partition. The discovery partition is visible, but the actual encrypted partition goes invisible. This post is for discussing the reasons of this kind of problems and how to fix the same.
First and foremost I would like to mention that there is no concrete resolution for this problem but there are two workarounds for dealing with such situations. Both the workarounds are mentioned below.
Method 1: Decrypt the partition using any Window 7 computer. This can be done by clicking on the start menu and typing bitlocker in it. This will list BitLocker Drive Encryption in the Start menu and we need to click on it. If the system asks for elevation then elevate the controls or just provide the Administrator’s password if prompted. Once the Window for BitLocker opens click on Turn Off BitLocker. You will find this option under Removable drive block and after clicking on this option click on Decrypt. This action decrypts the attached removable media and then it can be used on other Windows XP or Windows Vista computers without any problems.
Method 2: Format the removable media with FAT file system. Before doing this make sure that you connect your encrypted media to any Windows 7 computer and take the backup of data saved on it. To format the drive connect it to any Windows based computer and then open Computer window to view the drive once it gets detected and installed by the operating system. Now Right Click on the drive and click on Format in the context menu. When you have the Format Window select FAT as the file system and format the drive using it.
Please note that the methods given above are only workarounds and they sacrifice the BitLocking encryption done by Windows 7.