The rocket was launching a satellite into orbit for Saudi Arabian company Arabsat.
Liftoff was scheduled for Wednesday evening from Kennedy Space Center in Florida, but SpaceX postponed the launch.
Arabsat-6A is a high-capacity telecommunications satellite that will deliver television, radio, internet, and mobile communications to customers in the Middle East, Africa, and Europe.
SpaceX's Falcon Heavy proved its merit on Thursday night (April 11, ) when it took off into space on its first-ever commercial launch.
When the Falcon boosters return, the two side boosters descend together, side-by-side - coming back to their own landing zones as if you had been watching the flight on rewind.
The megarocket, which stands 230 tall, is the most powerful rocket now in operation.
SpaceX chief Elon Musk warned in advance things might go wrong, given the upgraded version of the rocket with unproven changes. "From our iconic launch pads at @NASAKennedy, we will continue to support the growing commercial space economy", NASA tweeted.
The Falcon Heavy differs from the Falcon 9 rocket. This is all part of SpaceX's plan to refurbish rocket boosters so they can be used again, lowering the cost of spaceflights.
After the 2018 Falcon Heavy launch, the center core missed the drone ship when only one of three engines ignited for the final landing burn.
SpaceX's Falcon Heavy carrying Arabsat-6A stands ready for launch at Kennedy Space Center.
SpaceX set a company record a year ago with 21 launches for customers.
The middle booster, after pushing the payload into space, returned almost ten minutes later for a successful landing on SpaceX's seafaring drone ship 645km off the Florida coast.
About 34 minutes after liftoff, the shiny silver satellite was successfully deployed. Before the rocket finally launched more than two years later, Musk suggested to several news outlets, including CNN, that the rocket could explode.