McLaren endured yet another disastrous start to testing after Fernando Alonso broke down inside the first hour on Friday.
The double world champion was completing only his seventh lap when he stopped at turn seven of Barcelona's Circuit de Catalunya.
McLaren are changing Alonso's engine as they investigate the cause of his car's failure, but the Spaniard is set to lose further valuable track time.
McLaren's latest issue marks the third day of this week's concluding four-day test in Spain in which the British team have encountered problems.
The new Formula One campaign gets under way in Melbourne in a fortnight's time.