Is this paintable caulk? If so, just touch it up with paint (tape on the ceiling above the caulk so you don't go over.

Another option would be a clean, simple crown moulding, something modern and not very ornate.

Who put it up? Ask them to remove it. I don't know why it was put there in the first place?

Leave it for awhile and see if it bothers you later. Painting would be a pain but probably the best option. Crown molding with a concrete ceiling and exposed electrical would not work.

I would do a very very plain trim against the wall to cover it up and add some character.

maybe something like this

Dig it out. Doesn't NEED caulk. Failing that, some more paint in a cup, a ladder, and an artist sized brush, with a pair of glasses : ).

Due to the nature of an urban loft with all the exposed elements, I'd say the best fix is a cup of paint, a flat artist's brush, a ladder, and a steady hand.

It actually was painted over. It still reflects through the paint. I even primed a small area and then painted over the caulk. It didn't help. The caulk was originally installed by the developer when it was built. I've had a 5-star contractor remodeling it and I paid $13,000 for the interior paint work. The contractor claims there is nothing they can do. I'm not buying it...

This may give you a better impression

Problem is you can't paint ceiling so now you don't have a clean edge to stop at. I would look into standard unsanded grout color caulk. They come in a large amount of colors and you can find one that is more closely matched and won't stick out as much.

Problem is scraping out what is there. Why would they use a non paintable caulk? Makes no sense.

I suspect that with the rough concrete ceiling, the first painters caulked the drywall to the concrete to get a nice finish, and it being spec I bet the walls were white so it didn't show. Now with darker walls the white line does show, but you are never going to get it off the concrete. You could wrap the wall paint onto the ceiling 1/4" to hide it but that doesn't seem great either.

The walls are actually lighter now than the original color. The original color was a light taupe and I recently had them paint the walls with Sherwin Williams Pure White Flat. The lighter color has made the caulk more pronounced. Up lighting makes the caulk glow at night. I'm finishing a
$160,000 remodeling but the caulk is all I notice. At this point I am considering having the ceilings painted.

I appreciate everyone's input

Well. I might run to the store for one by two's. Paint them a flat charcoal and run them 2" side to the concrete.........or even paint them wall color. Not really "trim" just a bit of cover and dimension with no "goo"

I don't want to appear stupid, but have you tried SANDING the caulk, and then the flat paint? Nail supply/beauty supply style fine sander, and just enough to get the "gloss" off to PAINT again in flat.

You did.

We also live in an urban loft with concrete ceilings. We painted our ceilings the same color as the white walls. They still have a nice concrete texture, but look cleaner to me. You could also consider painting them a concrete color that matches. First you need to figure out what is going to cover that caulk. Try a good oil based primer, since I'm guessing it's a silicone caulk, no latex will do.

These condos now sell for $800k to $1.8 million. Are developer basically raped new buyers when the building opened. They knew the building included significant and extensive construction defects but made the decision to not disclose them. One of the top floors caught on fire during construction and put them back two months. They did everything they could to catch up. Actually, several homeowners have drywalled the ceilings and concrete beams.

My contractor has mentioned using some type of "dulling spray paint"

I forgot one big issue. My remodeling had a 75-90 day construction period in the contract. Next week, we will start our 22nd month...

I have tried sanding caulk when my husband messed up a caulking job....he had insisted it could be done....wrong! It took me forever to dig out the caulk, using nails, fingernails, everything I could come up with.....very difficult! (And the caulk just laughed at the sandpaper/sander.....)

I apologize for what, I know, is going to sound like a really stupid question, but you did actually paint over the caulk, right? I'm assuming you tried and it didn't work because this is non-paintable caulk. In other words, your contractor used bathroom caulk instead of wall caulk. I would probably push for them to remove it and redo it, unless you think they will damage other things in the process, in which case I would do it myself. But if it is a non-paintable caulk, the only way to get rid of it is to actually remove it.

@sunshinehome can you tell me where the crown molding from the second photo you posted is from?

You have been bugged. A small micro strip of infrared LEDs are inside the caulk causing good night vision lighting in the rooms. The contractors are likely in on it. Be vigilant and aware of your surroundings.

If only I was into conspiracy theories

Your name does have "bug" in it....