If a machine encrypted with Encryption Desktop Drive encryption has these symptoms, the drive will need decrypting:
The recommended method of recovering an encrypted drive is to create Windows 10 WinPE recovery media because it boots to a command prompt and allows you to run PGPwde.exe, the Drive Encryption command line tool. Using the command line tool you can, for example, authenticate to the drive and copy important files from it.
If you do not have access to the WinPE recovery media, you can quickly create bootable USB media which will allow you to do the following:
Note that if a machine can already load bootguard but you cannot authenticate, it is unlikely that the bootable USB media will be of any help.
To create the bootable USB media please do the following on a machine that is running the same release of Encryption Desktop as the machine that has problems:
To use the USB drive
This is the bootguard screen:
This is the screen you see after authenticating:
The bootia32.efi, bootx64.efi and pgpcontents.tar files for release 10.5 are available here, the files for various 10.4.x releases are available here and the files for release 10.3.2 are available here.
Note that Symantec Encryption Desktop releases prior to 10.4.2 have reached their End of Service date.