Dell Latitude 7450 Boot Loop with Thunderbolt Dock

Hey everyone,

I'm hitting a wall with my Dell Latitude 7450 and my ThinkPad Thunderbolt 3 Dock (40AC). This thing is driving me crazy!

Basically, if I plug in the Thunderbolt dock before I even turn on my Latitude 7450, the laptop just gets stuck in a boot loop. All I see is the Dell logo with "Secured with Dell SafeBIOS" flashing over and over. I can't even get into the BIOS (F2 or F12) when the dock is connected like this.

But here's the kicker: if I just unplug the Thunderbolt cable, the laptop boots into Windows perfectly fine, no issues whatsoever.

And get this – once Windows is up and running, I can plug the Thunderbolt dock in, and everything works like a charm! All my stuff connected to the dock pops right up, and data transfers are smooth. It's only during that initial boot-up phase that it freaks out.

I've already tried the usual suspects:

• Updated the BIOS on my Latitude 7450 to the latest version.

• Updated the firmware on the ThinkPad dock.

• Dug through the BIOS settings to make sure Thunderbolt was enabled and set up right.

Has anyone else run into this with their Dell Latitude 7450 or another Dell laptop and a Thunderbolt dock? Seriously, any ideas on what else I can try? It's a real pain to have to boot my laptop then plug in the dock every single time.

Thanks a bunch for any help you can offer!