Former BBC chief Mark Thompson has denied misleading MPs over a scheme that was scrapped at a cost of around £100m.
Mr Thompson, who was previously the corporation's director-general, told the Public Accounts Committee the Digital Media Initiative "failed as a project" and that he "wanted to say sorry".
But asked about previous evidence where he said DMI was working well, Mr Thompson told the committee: "I don't believe I have misled you on any other matter and I don't believe I misled you knowingly on this one".
He told the committee his evidence was "faithful and accurate account of my understanding of the project at that point".
The BBC's former chief technology officer, John Linwood, was earlier accused of "avoiding key meetings" in an effort to dodge blame over the doomed initiative.
Committee member Richard Bacon MP told Mr Linwood: "You were known inside the BBC for avoiding key meetings so you could say you weren't there."
Mr Linwood told the panel he was "not responsible" for drawing up "the business case" for the project which he said was already "behind track" when he started work on it.
"When I joined the BBC the project was running 18 months to two years behind track," he said.
The DMI - an effort to create an integrated digital production and archiving system - was scrapped by current director-general Tony Hall in his first weeks in the job having cost £100m of licence fee-payer's cash.
A report by the National Audit Office (NAO) blasted the scheme and said the BBC Executive "did not have sufficient grip" on the project and did not properly assess the system to see whether it was "technically sound".
DMI was meant to allow staff to handle all aspects of video and audio content from their desks, but after years of difficulties - during which £125.9m was spent on it - it was axed last year leaving a net cost of £98.4m.
It emerged last week that Mr Linwood - who was paid a salary of £280,000 - was sacked weeks after being suspended over the multi- million-pound failure last May.
Mr Linwood said Mr Hall had been too hasty in writing off "tens of millions" of pounds of IT equipment.
"They wrote off software that was working and they wrote off infrastructure that was working," he said.
"They were written off because the business decided not to use them."
MPs also asked Caroline Thomson, the BBC's former chief operating officer, about her pay-off, which saw her leave the corporation with around £700,000 and a £2m pension pot.
Asked if she would return some of that money, she said: "No."
"I was made redundant, I was made redundant, I didn't want to be made redundant," she said.
"I wanted to stay and work. I was paid a lot of money, I completely accept that, but it was my contractual entitlement and no more."