If more than one HDD or SSD drive is present in a computer when Windows 7 is installed, a System Reserved partition may be installed on a different drive other than the Windows boot files. For example, Windows Disk Management shows a System Reserved partition on Disk 0 with the attributes System and Active. It shows a C drive partition on Disk 1 with the Boot attribute.
The system boots correctly when Symantec Drive Encryption is not installed.
After encrypting the C drive partition, BootGuard fails to load and Windows fails to start with the error:
"The boot selection failed because a required device is inaccessible."
Symantec Drive Encryption is not designed to work with systems that have a Windows 7 System Reserved partition on a secondary drive.
Use one of the following
The following workaround avoids reinstalling Windows 7 on a system with 2 drives with the System Reserved partition on a different disk to the C partition. However, it will make the System Reserved partition redundant:
Symantec Drive Encryption or PGP Whole Disk Encryption