GTrusted

To use pre-Thunderbolt 3 peripherals like the LaCie Rugged Thunderbolt External Hard Drive (USB 3.1 Gen 1) on the Dell XPS 13 9350 Laptop, you'll need to use special adapters like the StarTech Thunderbolt 3 to Thunderbolt Adapter.

Once you plug the StarTech Thunderbolt 3 to Thunderbolt Adapter into the Thunderbolt 3 port of the Dell XPS 13, a message window pops up on the bottom right corner of your screen, telling you to enable the Thunderbolt device before use.  Note, you will see the Thunderbolt device that is connected to the StarTech Thunderbolt 3 to Thunderbolt Adapter as the device that needs to be approved (and not the adapter itself).

After selecting 'Connect Once' or 'Always Connect" in the Approve Thunderbolt Devices window, you can see the LaCie Rugged Thunderbolt External Hard Drive (USB 3.1 Gen 1) show up in the PC's Device Manager.

In the Windows Device Manager, we can also confirm the LaCie Rugged Thunderbolt External Hard Drive (USB 3.1 Gen 1) enumerates as a SATA AHCI Controller within the PCI Express Root Complex.

Finally, we could also confirm that file transfers are working well.

Given the problems that we have seen with the StarTech Thunderbolt 3 to Thunderbolt Adapter working with other PC's, we were happy to see it working well with the Dell XPS 13 9350 Laptop, allowing it to connect to pre-Thunderbolt 3 peripherals like the LaCie Rugged Thunderbolt External Hard Drive (USB 3.1 Gen 1).