"Regrettably we have not been able to find common ground with Jost with regard to what is and will be needed to make the team successful again," a Formula One spokesman said.
"As a result, we have agreed that he will leave McLaren Racing and will now consider other opportunities."
Capito, a former Volkswagen motorsport director, was recruited by Dennis in January last year but did not start work at Honda-powered McLaren until September due to previous commitments.
McLaren shareholders removed Dennis in November, with American Zak Brown coming in as the new executive director.
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Brown has been working alongside chief operating officer Jonathan Neale, with Eric Boullier in charge of day-to-day management at the former world champions who last won a grand prix in 2012.
Spaniard Fernando Alonso and Belgian rookie Stoffel Vandoorne are the team's 2017 drivers with the new season starting in Australia on March 26.
(Reporting by Alan Baldwin; Editing by Robin Pomeroy)
