Livingston have parted company with Marcio Maximo only four months into his reign as head coach.
Marcio Maximo is heading back to Brazil on Wednesday
The club's chairman, Dominic Keane, confirmed the news, disclosed earlier by BBC Sport, that the 40-year-old Brazilian had resigned.
But a disappointed Keane has refused to disclose the "personal" reasons for the departure.
Club sources suggest that Maximo was homesick, although it is also known that some players were unhappy with his methods.
Keane told his club's website: "Despite numerous meetings between myself and Marcio, when I made every effort to convince him to stay with us and see through the professional job he was doing at the club, I am left with no option but to respect that decision - difficult as it has proved to be.
"I sympathise fully with the personal reasons which prompted Marcio's request to be allowed to leave and I have assured Marcio that those reasons will remain a private matter between ourselves.
"It took great courage for him to come to Scotland and, as far as the history of Livingston FC is concerned, Marcio's efforts will be appreciated for years to come."
Maximo insisted that, despite his decision, he had enjoyed his time with the Scottish Premier League club and thanked the players, staff, fans and, especially, the chairman.
"He is committed to a forward-looking approach to football and I hope he continues to follow that philosophy in the future," Maximo said of Keane.
"I know that it is often difficult to implement new ideas in football, but I truly believe that Livingston Football Club has great potential and will, in the short term, affirm its place as one of the most influential and respected clubs in Scotland."
Maximo's time at the City Stadium was dogged by controversy and unconvincing performances that have failed to significantly revive the club's fortunes.
Previous boss Jim Leishman was unhappy at being moved into a chief executive role to make way for Maximo becoming the first Brazilian to lead a British club.
Leishman soon left for a similar upstairs role with hometown club Dunfermline Athletic.
And Keane's Brazilian experiment at Livingston got off to a bad start when Leishman's assistant, Davie Hay, and Maximo appeared to disagree about who had the final say in picking the team.
Hay eventually took a back seat but is poised to take over team matters for Saturday's game against Hibernian at Easter Road.
Livingston presently lie eighth, one spot above last season's finish, seven points clear of relegation favourites Partick Thistle but five points adrift of third-top Hearts.
Maximo had turned down an offer of a contract extension from the Grand Cayman Islands, where he was technical director, to sign a one-year deal with Livingston.
He came highly rated, having nurtured World Cup winners Ronaldo and former Manchester United target Ronaldinho during his time as coach of Brazil's under-17 and under-20 sides.
The Brazilian, full name Marcio Maximo Barcellos, is due to leave Scotland for Brazil on Wednesday.