It’s a debate that can split editors and writers: which of the following is right?
However some people disagreed with the move.
or
However, some people disagreed with the move.
For me, it would always be the second option, for two reasons.
First, the comma imitates the natural way that the sentence would be vocalised – there would always be a small pause to indicate that the following part was the main substance of the sentence.
And second, “however” has another meaning, namely “in whatever way”, for example “However you look at it, it’s a bad idea.” For this reason alone it’s always worth putting the comma after “However” because good writing is always about clarity, and ensuring readers never have to read a sentence twice to understand it. Consider this sentence:
However you like your coffee without milk, so I’ll leave it black.
I bet when you started reading that sentence in your mind, you were thinking about the way the person liked their coffee, but then it unfolded differently. In contrast,
However, you like your coffee without milk, so I’ll leave it black.
is unambiguous.
However you look at it, where “however” is used to mean “despite this” at the start of a sentence, it’s best to follow it with a comma.