Machine Head were forced to cancel their performance in Portland, Oregon at the last minute on Saturday after their tour bus broke down on the way to the gig.
Sincerest apologies from the band to all of the fans expecting to see Machine Head play tonight. Trust that they're as disappointed as you are by these maddening circumstances
The concert would have marked frontman Robb Flynn's return to the band following emergency surgery on 14 November to treat complications from a double inguinal hernia.
Machine Head, who are touring North America with Dethklok, All That Remains and Black Dahlia Murder, apologised to fans for the cancellation of their set and expressed their frustration at the situation.
A statement from the group on Saturday reads, "Machine Head are currently stuck on the side of the road a few hours outside of Portland after their bus broke down earlier this afternoon, and unfortunately must announce that they will miss tonight's show.
"Pouring rain and heinous traffic mean that even if they could get the bus running, they'd never make it in time, frustrating all involved to no end.
"Sincerest apologies from the band to all of the fans expecting to see Machine Head play tonight. Trust that they're as disappointed as you are by these maddening circumstances".
The rest of the billed acts went ahead with the show as scheduled.