According to Arlov Grammatically

Many instructors urge their students not to start their sentences with the word â€Å"but†, or any other coordination conjunction for that matter. This can be disheartening for students because we commonly speak with our sentences beginning with a conjunction. However, writing is not like speaking. There are two schools of thought on beginning a sentence with the word, â€Å"but†. According to Arlov, â€Å"Grammatically, it is correct to start a sentence with but or any other FANBOYS conjunction.However, your instructors may discourage the practice for two good reasons† (343). She goes on to list the reasons. One good reason not to begin a sentence with the word but is because it is informal and casual. Academic writing is not usually casual or informal, and using â€Å"but† at the beginning of a sentence may make a more formal paper appear less than well thought out.While it is OK for some sorts of writing such as narrative or dialog, a professional paper is seldom written with coordination conjunctions at the beginning of sentences. Also, using words like â€Å"but† is addictive! It is easy to use and overuse. Arlov advises using conjunctions to begin sentences sparingly so as not to make it a hard habit to break. The other side of the issue says using but is just like using any other word to begin a sentence, and therefore, there is nothing wrong with it.