I am unsure about whether I need "are" after "but" in the following sentence:

If you are looking for a new career direction but are not sure which way to go, you have come to the right place.

Is it redundant to have "are" there? Is there any standard rule of grammar which applies here?

This is not a case of redundancy in my opinion.
How much you want to repeat in a parallel structure depends on the style you want to use. I think that the more you repeat, the less likely there will be confusion about the meaning of your message, but also the more likely you will sound more formal or stuffy.

There is room for differences of opinion on this. There is no rule. Maybe others will contribute their opinions as well.

Emotion: smile
The 'are' is necessary.

Without it, it is false parallelism: the first 'are' is part of a continuous verb structure, but the second 'are' is the copulative 'be'.

The second 'are' can be omitted in a true parallel structure like this:

'If you are looking for a new career direction but not finding it, you have come to the right place.'
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OK. I can accept that it is a "false parallel structure".
Nevertheless, although my choice personally would be to use the "are", I didn't find its omission particularly jarring on the ear! Emotion: smile
Hi, Mr. M.
Did I get it right that, according to this false parallelism rule, the sentence “I am sad and waiting for a comfort” is constructed incorrectly, the right version being “I am sad and am waiting for a comfort”? As a matter of fact, the latter sounds a bit awkward to me…
I agree, and that's why rules seldom work with language. 'I am sad and waiting for a comfort' is short and straightforward enough to contravene the 'rule'.
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Mister Micawber,

The "are" in the original question just sounded slightly better to me, though I couldn't pinpoint why. I read through your explanations and found them very well done. The example seems very subtle but as I read your rationale, I understood.

Just thought I would pass along my compliments.

Thanks everyone for your insights.

I am more comfortable using "are" in the original sentence.