The Fringe ticketing problems emerged in the weeks running up to the festival
The Edinburgh Fringe has launched an independent inquiry into its own box office following weeks of problems.
Many shows have been oversold and some customers have been left without tickets due to a new box office system.
Fringe board members attended an emergency meeting for representatives from most of its 247 venues.
Fringe director Jon Morgan said the inquiry should offer vital information to help them prepare for next year's event.
He said he was confident the system could cope until the end of the Fringe in about two weeks' time.
In the run-up to the Fringe, technical issues meant thousands of people were still waiting for tickets only two weeks before the event began.
Printing problems meant the deadline for mailing tickets was missed.
Other shows have been hit with problems of overselling, and the Fringe box office has advised ticket holders to check the website for details of how to collect tickets for specific performances.
John Burrow, director of the Acoustic Music Centre at St Bride's, said: "I think it's disgraceful because the people in the Fringe office are dealing with the livelihoods of all types of people.
"Someone in the Fringe has to stand up and say mea culpa. Every penny counts in the Fringe, nobody comes here and expects to drive away in a Porsche.
"We all (independent venues) support the ethos of the Fringe, and we warn the artists, yes there's great camaraderie, but you can't turn your back or somebody will steal your audience."
Gillchrist Muir, of theatre company Handsome Chin, said: "Effectively the Fringe are redundant for us this year.
"I'm not sure what was wrong with the old system really because it's created a big headache for everyone this year."
Michael Everts, of production company Theatrical Theatrics, said: "We had four friends turned away from the venue because C venues were getting reports that we had sold out.
"They were reporting sell outs when we'd only actually sold about 15 tickets."
Simon Peers, from Edinburgh Theatre Arts, said: "We depend on pre-bookings and that pre-booking period was missed.
"Once people are in the town centre, they're not going to walk three or four miles to a venue that's on the outskirts so we've lost at least 300 tickets for the course of the Fringe.