What it means
たくなかった expresses that someone did not want to do an action at a past time. It attaches to the masu-stem of a verb and is the familiar form. The polite counterpart is たくありませんでした. The expression focuses on a lack of desire, not inability or failure to do the action.
Usage note
The subject of たい expressions is normally the speaker or another person whose wishes are being directly discussed. Do not confuse たくなかった with a past negative form meaning that the action did not happen; it specifically means that the person did not want to do it.
How to use it
私はその映画を見たくありませんでした。
I did not want to watch that movie.
私はその映画を見たくなかった。
I did not want to watch that movie.
Example sentences
昨日は宿題をしたくなかった。
I did not want to do my homework yesterday.
妹は人前で歌いたくなかった。
My younger sister did not want to sing in front of people.
雨が降っていたので、駅まで歩きたくなかった。
Because it was raining, I did not want to walk to the station.
その映画は怖そうだったので、見たくなかった。
Because that movie looked scary, I did not want to watch it.