Can you be denied entry to Schengen zone if you hold a valid D visa?

Question

Only reason I'm asking this question is that I want to fly home to the US to visit family in early February, but my current D visa (Spain) expires mid-March. I am approved for a residence permit in Sweden since I will be studying there from January to June, however I was instructed by the Swedish Migration Agency to pick up my permit in Sweden since I am a visa-free passport holder.

If I were to get a direct flight from US to Sweden I wouldn't worry about it since I know it's normal for students to travel to Sweden before getting their visa, and the border control there knows how the migration system works. However the only affordable flight I've found goes through Portugal (TAPAir) and I'm worried the Portuguese border control will question my motives (why flying back and forth, why is my flight connecting to Sweden and not Spain, etc) and will not let me in if I say I'm going to Sweden to pick up my residence permit.

Therefore my question is, will they even care or question me if I have a D visa for Spain that is valid until mid-March? Are they even able to deny entry to someone who has a valid D visa? I don't mind answering questions and being interviewed more than usual, I'm just worried about the possibility of being denied entry. I've already left and re-entered once throughout my D visa period with no questions asked (France as port of entry) but it was around Christmas when it's quite normal to travel.

Answer 1

Border guard is typically interested in the following

1. You do not become an illegal worker/immigrant
2. You are not travelling to commit serious crimes

The D visa pretty much clears the first concern as for the duration of that you are allowed to stay and work (limited hours but still)

It says nothing about the second concern and a few flights in themselves will not raise red flags. It's fully normal to take non-direct flights and TAP is known to be cheap anyways.

So based on what you said -- which might not be the full story of course -- and without being actual border guard I would say you shouldn't be worried.

Edit: reviewing this a day later, I see I haven't answered the question in the title "Can you be denied entry to Schengen zone if you hold a valid D visa?" -- well, of course. Show up with a kilogram of heroin and see what happens. Even if I don't want to be that glib, border control have the final say whether you are allowed to enter. But still, there are checks and balances in place and they won't just deny you because they have a bad day. The Schengen Borders Code has a section on the entry and exit of third-country nationals and beyond obvious things such as counterfeited documents we have:

verification that the third-country national concerned, his or her means of transport and the objects he or she is transporting are not likely to jeopardise the public policy, internal security, public health or international relations of any of the Member States.

This is obviously a "rubber" paragraph -- but it shows there needs to be a rather substantial problem for a denial.