Name: HL DT ST DVD RW GSA T21N ATA Device Driver
Author: LG

Question 1

Install fails or Device Manager shows Code 39/41?

Accepted Answer

Windows’ native `cdrom.sys` is usually sufficient. Uninstall the HL-DT-ST GSA-T21N under DVD/CD-ROM drives, reboot, and let Windows reinstall it. Remove old LG or third-party burning-suite drivers first; don’t force an unsigned legacy driver.

Question 2

Drive not detected?

Accepted Answer

Confirm the GSA-T21N appears in BIOS/UEFI. Reseat the SATA/power or slim-drive adapter connection, check the BIOS SATA mode, and try another cable/port. In Windows, scan for hardware changes; for Code 19, reset CD/DVD filter drivers.

Question 3

Version/firmware conflicts?

Accepted Answer

Match firmware exactly to GSA-T21N—generic LG GSA firmware can brick the drive. Roll back a newly updated driver, and avoid multiple burning packages that install conflicting filter drivers.