Humans and all other animals move, rarely still for long, esp. in a group.....1/30 to 1/60 and even then, someone in a group will be moving/twitching/winking/scratching/breathing(some folks/animals move when they breath)/etc. etc. Higher ISO is always helpful, and not the "noise generator" it used to be. Flash or photo/video lights are most helpful.

Shame, maybe you could sell it for parts. The multi bent pin situation sucks!!

Assuming you are trying a new card;
It might have bent a pin, or it could have debris still in the pin contact area, try looking in again with good light and magnifying lens. The broken piece might have bent a contact pin. These can often be straightened, but it is a challenge due to size and access issues.
The ERR message could possibly be cleared by a reset.....and/or method in next sentence................
You might also try turning off, removing the battery, turn on for few seconds( maybe 30) and off with battery out, then re-install battery and turn on camera, see if you still get the message.

In the long run, mine failed due to similar issue around 25K clicks, it is still working fine on the second slot at near 50K clicks....I have a micro sd card adapter/holder in the second slot all the time, I remove the card with tweezers (so no wear on second slot/pins/locking mechanism). This may be the way to go if the ERR does not clear.

Good luck with you effort!!!

Does the card slot communicate at all with the camera? Have you tried the old clean the contacts with alcohol trick? Does it have one or two slots? Tell me more, I'll see if I can come up with something/
om

Look in the slot; Even if you don't see/know what to look for - use vacuum cleaner hose attached to one of those thin opening attachments (for cleaning in between sofa cushions and such) to concentrate the suction. If no debris is evident, it could be that the lock mechanism has failed/is failing. Until corrective success, switch to 2nd card slot, designate it as primary...that way you can continue to use the camera. My D7100 1st slot failed at about 25K clicks, I could not fix it and the card would not read - so I switched to 2nd slot as primary....and I changed my operating method going forward.

Also:
Try a brand new card (preferably a micro card with adapter/holder), if it locks in place, LEAVE IT THERE!! Just remove the micro card from the adapter from now on - If it will not lock in place, but the card will still work, try using a small piece of foam or plastic to hold the card in via the card slot door (this may/may not be feasible for long term), but will tell you if the card slot is still communicating with the card.

Consider the following:
From now on with second slot; Use only Micro SD card types, and when taking card out or putting in, pull the micro card from the holder, leaving the card adapter/holder in place permanently in the card slot, this will eliminate any wear and tear on the 2nd card slot mechanism. If you have trouble grasping the micro card, use tweezers while leaving the adapter "locked" in place. This method works well, I have continued to use my workhorse D7100 for several years now with only the second slot, I never remove the micro card adapter/holder, just pull the card from it.

Repair by a camera repair shop would probably cost as much as a used replacement body, but since you have a second slot, you have time to determine what you want to do.

You can also alternate downloads by using the cable instead of pulling the card.
My $.02

Another pointless argument to me - the "handheld" photos attached and viewed normally are just fine for what they are and what they represent - pixel peeping or not, viewed at normal distances they seem fine.

Overspent/need money for Christmas - grass was greener in the ads - realized now we need more new lenses - decided (now that one is in hand) that there was a better model - better, but not that much $$ better - your idea here -

When you need the reach, "you need the reach".... enjoy the lens, it's a wonderful gift to receive!!!! The more time you spend shooting with it the more you will like it, especially with a stout tripod and a trigger....

So now we know where the name "Moondoggie" came from... . . . . ............

Good stuff Bill de....to our OP...try it see what you think!!! Like Jerry noted - free is a good thing...and you can always move on if you need to.....

Download the Nikon processing stuff for free from Nikon web site, try it out and then decide..up to you!

Pixel Peeping has it's place, but 97% of the time the overall image effect (not talking the out-of-focus mess) is more important, what it conveys, pleasure it gives, etc. etc. Distance viewer is from the photo/viewscreen matters, or not....many photos that might not pass the "peep" test perfection requirements may be absolutely georgous from several feet away (normal gallery viewing distance).

I do "Peep" for certain photos: when shooting bird phtos, looking at feather structure, looking for lack of movement (stills), feeling of movement (flight), etc....but in general, the current crop of cameras I have, from 8-10 MP older models to 20-24 MP DSLR and Mirrorless...if I'm on my game, I get a fine shot....they (some better than others) focus at least as well (or much better, as fast or faster) than my old eyes, and when I peep, keeping in mind how it will be viewed, they usually do not disappoint. I find the current and even older technology allows me to spend much more time on the composition and effect the finished photo will give. AND, sometimes "too sharp" can take away from the "artsey" feel, whimsical mood, etc. - think about the paintings you've drooled over in museums - how sharp were they, how far from the painting did you view, etc.???

Again, "Peeping" has it's place/need, but it is not the principle overiding decision maker, it is more of a tool. I'm not defending poorly executed, out-of-focus work, and there is a delete key for that, but in general if a photo looks sharp at 2-3 feet from the viewscreen or hung on a wall, or at normal viewing distance on a large screen tv, then all the other factors take prominance (composition/subject/situation, etc.).
My $.02

Really excellent series!!! Thanks for sharing!! I'd do it again too!!

To each their own, (my opinion and my process, serves me well, others are free to use, or not) - no harm no foul - the trouble with "Chicken Little" was a lack of deductive reasoning, failure to recognize predictive failure paths, and no way to act on the issue - and unfortunately, stuff falls out of the sky everyday...... No the Mfg's don't recommend "not removing", they are also hopeful that items will break down and fail over time, it helps to insure future purchases, and the repair window for electronics continues to shorten - it is a global/industry wide planned obsolescence/replacement cycle, they don't want us to repair anything, just keep buying new ones!

I just recognize the path to failures based on industrial experience, and predictive maintenance/failure routes, and the card mechanism - card pins/contacts and lock/eject mechanism is one weak link.... not the only one, unfortunately.

Predictive maintenance = It is how we keep fleets of planes (think for instance of the B-52) flying, ships, trucks and trains, etc. operational, it was a prime function for me during my days with Space Shuttle....we were working toward the same predictive maintenance path that worked so well for B-52. They (NASA) did actually intend to keep the Shuttle as a viable spacecraft well into the 2030's-2050's....reality was that the budget (and the way the program was structured and contracted - basically turned it into a WPA program like the one's during the 1930's) and wasn't sustainable, would not support it, too fat with people, and not fat enough with upgrade engineering, and the Space Shuttle budget was not very large, on a year to year basis, as those things go.

Give my regards to Chicken Little, he needs all the help he can get!!!

Something is going to suffer the ware-n-tear in mechanical connection (even in electro-mechanical components), no way out of that....I just looked at the whole process (pretty much the same for every camera) and decided that the camera should be subjected to the least amount of mechanical sufferage, that was when the micro SD thing set off a lightbulb in my skull (Not saying I invented the idea, just "saw the light"!! It's a bit more invoilved, but only as far as having to use tweasers to get ahold of the card and not remove the card holder.....not perfect, but much less mechanical actuations, pluggin in and taking out, mechanical latch for card, springy contacts, etc. The little micro cards are up to the task...it works well for me, esp. in light of having one working card slot.