The #23 ORECA 07-Gibson of Oliver Jarvis, Tom Blomqvist and Josh Pierson controlled the first half of Friday's Sebring 1000 Miles from pole position before coming to a halt in the fourth hour.
United traced the stoppage to an electrical shut-off caused by a broken in-car TV camera fixture which it says was not installed by the team.
"It’s times like this when you love racing and hate racing," said Dean.
"The positives are the pace from both cars. I don’t think anyone would have touched us here with a clean race, as demonstrated by the #23 with Olly Jarvis and Josh Pierson pulling away.
"The work that’s gone in to have such pace is phenomenal, the drivers are saying the cars are incredible... so it’s cruel when the win is taken away from the #23 like that, but we have to analyse it.
"I know it was something we didn’t install in the car... it’s one in a million, but we have to make sure it doesn’t happen again."
Pierson was only four laps away from completing a triple-stint and handing over to Blomqvist when the drama occurred.
“The race started out really positive," said the American teenager, who won on his WEC debut at Sebring last year.
"We had a great first stint from Olly, I jumped in to do the triple and had strong pace throughout, but then with four laps to go the TV camera broke and ended our race.
"It’s really hard to put into words how it feels when it’s not yours or the team’s fault. It makes it even worse that something outside our control ended up putting the car back in the garage.
"But we’ve got a full season ahead so now it’s about picking up the pieces and seeing how we can salvage the championship."
While the #23 car dropped out of the running, United's #22 entry shared by Phil Hanson, Filipe Albuquerque and rookie Frederick Lubin finished second behind the class-winning Jota ORECA of David Beckmann, Will Stevens and Yifei Ye.
With the Jota car not registered for full-season points, instead acting as a placeholder for the team's Hypercar entry that will come on stream at Spa in late April, United's #22 drivers lead the LMP2 standings.
Albuquerque said: "United Autosports was in its own league. We could see the #23 completely dominating this race, but unfortunately they had something really unusual happen with a broken camera.
"Then we fought back, putting everybody on the limit because we came back from one minute off without safety cars... it was pure pace.
"The car was just brilliant, it should have been a 1-2 but we are leading the championship because the car that won is not a full-timer.
"At the end of the day we need to be really proud of what we've done and happy with the result we have."
