Can "however" and "but" be used interchangeably?

Question

Can they be used interchangeably? If not, in which situations should I use the former and the latter?

Answer 1

When they're interchangeable...

The following sentences are typical uses of "but/however" (note the different punctuation, hat tip:@snailboat):

I wanted to go to the store, but I didn't have enough time.
I wanted to go to the store; however, I didn't have enough time.

In these sentences, the two words are essentially interchangeable. The version with "but" is probably a little more informal.

When they're not...

There are other uses of the two words, however, where they are not interchangeable. Here are a few examples:

Examples where you can use only "but"...

• I liked all but one of the songs on that album. [used as a preposition to mean "except"]
• I am but your humble servant. [used as an adverb to mean "only"]
• I don't want to hear any ifs, ands, or buts. [used as a noun as part of an idiom]

Examples where you can use only "however"...

• I'll pay for it however I can. [used as an adverb to mean "in whatever way"]
• There are other uses of the two words, however, where they are not interchangeable. [used as an aside]