Consider the following scenario:
You have removable media that is formatted with the FAT file system. For example, you have a USB flash drive, an SD card, or a memory stick that is formatted with the FAT file system.
You use BitLocker Drive Encryption to encrypt the removable media in Windows 7.
In this scenario, when you connect this encrypted removable media to a device or to a Windows operating system other than Windows 7, you experience the following symptoms:
If you connect the media to a Windows Vista or a Windows XP-based computer, the media is displayed to use the FAT32 file system. The media has no free space, and you do not have write access to it.
If you connect the media to a device, such as a digital camera, MP3 player, or mobile phone, the media may not work.
Note To view the file system and the capacity of the removable media, right-click the removable disk drive, and then click Properties.
When you turn on BitLocker for the removable media in Windows 7, Windows 7 creates a "discovery volume" that is formatted with the FAT32 file system on the removable media. The space that the discovery volume uses is virtualized and invisible to the Windows 7 user.
When you connect the media to a computer that is running Windows Vista or Windows XP, the FAT32 discovery volume is visible. It contains the BitLocker To Go (BitLocckerToGo.exe) auto-run application that enables you to read to the data that is on the encrypted media. However, the original BitLocked volume becomes invisible. Therefore, the system identifies the media as using the FAT32 format. If the media does not work on a device, this problem may occur because the device requires the FAT file system.
To work around this problem, use one of the following methods.
Methods 1: Decrypt the removable media in Windows 7
Connect the removable media to the Windows 7-based computer.
Click Start, type bitlocker in the Start Search box, and then click BitLocker Drive Encryption in the Programs list.
Click Turn Off BitLocker under the removable drive, and then click Decrypt.
Methods 2: Format the removable media with the FAT file system
Important Back up your data from the removable media before you perform this procedure.
Connect the removable media to a Windows-based computer.
Click Start, click Computer, right-click the removable disk drive, and then click Format.
In the Format dialog box, select FAT in the File system list.
Select the Quick Format box if you want to perform a quick format.
This behavior is by design.