Ann Limb announced her resignation last week after three years at the helm of the organisation that runs the learndirect online learning centres.
She insists her departure is amicable, but in a statement announcing her resignation, Ufi said "this is an appropriate time to strengthen Ufi's commercial leadership".
Ufi is believed to be seeking a successor who can win private-sector cash for the organisation that is currently entirely publicly funded. It also wants to establish strong links with employers in delivering work-based learning.
Dr Limb is believed to have clashed with Ufi's chairman Sir Anthony Greener over strategies to improve learndirect's performance, which was criticised earlier this year by the Learning and Skills Council.
The LSC's report raised concerns that learndirect reached only 65 per cent of its training target in its first year, despite huge spending. It spent pound;8 million on advertising in 20023 and a further pound;10m on other marketing. This amounts to 8.8 per cent of its budget, compared with the 3 per cent that colleges typically spend on these activities.
Ufi's statement said: "With the company's plans to diversify funding streams through both public and private sector routes, this is an appropriate time to strengthen Ufi's commercial leadership."
It added: "Dr Limb has played a leading part in establishing Ufi as the UK's most important publicly-funded e-learning provider, and flagship of the Government's e-learning strategy."
It said her resignation from the end of June was accepted "with regret".
Sir Anthony Greener added that Dr Limb had "put Ufilearndirect on the map, and established it as a significant force in the educational landscape."
Pending the appointment of a successor, Dr Limb will hand over day-to-day responsibility to her deputy Pablo Lloyd.
Dr Limb told FEFocus that she was resigning now because she "wanted to get out on a high".
"I have spent three years taking learndirect from where it was when I inherited it to where it is now, and that is a good innings as far as I am concerned.
"I would rather leave feeling that achievement as something to be proud of, rather than run out of creativity and steam."
She said she achieved her three objectives for learndirect; delivering coherence with UK Online centres, delivering quality, and contributing to the Skills for Life agenda by attracting "huge numbers" of adult learners.
Learndirect has just completed a major restructuring with the appointment of 23 new hub operators through which LSC funding will be directed.
Some market analysts believe Dr Limb's departure could signal a crisis for Ufilearndirect. Roy Baldwin, director of Creative Gateway, said: "If I was a gambling man I would not bet on learndirect being around in 18 months time.
"It has unfortunately become inflexible, hugely bureaucratic and unnecessarily expensive."