Use PolicyServer to deploy a policy that decrypts all disks for a specific group. Set the Encrypt Device value to No.
For details, see the Endpoint Encryption 6.0 PolicyServer MMC Guide.
Uninstalling Full Disk Encryption automatically decrypts all disks attached to a device.
For uninstallation steps, see the Endpoint Encryption Installation Guide.
Start disk decryption from the Recovery Console in preboot.
For details, see Using Decrypt Disk in Preboot.
Use the preboot's Decrypt Disk function only if you have problems booting into Windows. If there are no issues accessing Full Disk Encryption from Windows, Trend Micro recommends using PolicyServer or the Full Disk Encryption uninstaller to decrypt disks.