The verb "uncomplete" does not exist. If you want to express that someone took something that had been complete and made it incomplete, you would have to say: He removed the cog wheel from the engine, rendering it incomplete.

What does Uncomplete mean?

: not brought to an end or to the desired final state : not completed an uncompleted portrait/project an uncompleted crossword puzzle.

What is difference between incomplete and Uncomplete?

Incomplete means (and meant) that not all parts are present. The Latin negative in- prefix was already attached, before the word was borrowed. The opposite of uncompleted is completed; i.e, finished, done (of activities). Completed is the past participle of the English verb complete, not a Latin verb.