Incomplete: adjective - not complete; not fully formed; unfinished; not whole or thorough; lacking something, imperfect.
Uncompleted: adjective - not completed.
I display these alternatives here, as they came up in a discussion at my writers’ group a short while ago. We spent a little while discussing the meanings of the two words and came away without any conclusion, so I looked them up in the Shorter Oxford English Dictionary (my standard reference dictionary, and the one from which the definitions were taken: thank you to the Oxford Press). Apart from the fact that ‘uncompleted’ has only one, very specific, meaning, I can discern no essential difference between the two terms used in the context of the sentence we were discussing at the time. I’d still go for ‘incomplete’, simply because I find ‘uncompleted’ has an ugly sound to it. It goes to show that, in English, the chosen word can often be a matter of taste and preference without actually altering meaning in a significant way. Agreed?
The picture is just a shot I took a while ago. Zemanta, the widget I use for illustrations, came up with nothing suitable this time.