User blog comment:SolZen321/The biggest Grammatical Mistakes/@comment-1030114-20160321075236/@comment-5527544-20160321113505

As someone who went through an English Course, who would be penalized if a sentence ever started with 'But' no, we've come to accept it, but the fact remains, the purpose of the word is not to be the start of the sentence but to connect to smaller sentences.

You cannot, you should not, start a sentence with 'but'.