Hi Bill, here is a link to a an Apple site which gives an idea of how to check 
for your Nikon D3200. It is for a previous version of the operating system, but 
will be roughly the same method of using Disk Utility to see if either the SD 
card or the camera shows up when connected to your MacBook Air.

https://discussions.apple.com/thread/7393940

Older cameras used a different protocol for connection to computers, but I 
imagine that you will have already updated the protocol on the camera for the 
previous system and that would be the same for Mojave. You are instructing your 
camera to be viewable as a HD.

However, there is no earthly reason for the MacBook Air to not recognise the 
files on your SD card reader. I did a quick google search and connecting older 
cameras may be a problem, but there should be no problem with loading any 
camera files from an SD card reader. This is speaking as an enthusiast 
photographer who has used lots of different cameras. I always use an SD card 
reader.

If you don’t have a problem with your USB cord and the USB port on your MacBook 
Air has been working fine for everything else, the only other problem might be 
a slightly corrupted SD card. In other words, try a different SD card in the 
reader.

Cheers, Susan.

Sent from my iPad

> On 18 Feb 2019, at 5:58 am, Ronni Brown <[email protected]> wrote:
> 
> Hi Bill,
> 
> Check here for compatibility in Mojave
> https://www.nikonimgsupport.com/na/NSG_article?articleNo=000042305&lang=en_SG
> 
> Kind Regards,
> Ronni
> 
>  Ronni Brown’s iPad Pro 12.9-inch 256GB 
> 
> 
>> On 18 Feb 2019, at 4:57 am, Juliet Kitson <[email protected]> wrote:
>> 
>> Thanks Susan tried all those the Nikon uses a different USB cable to the 
>> card reader .
>> Regards Bill
>> 
>>> On Sun, Feb 17, 2019 at 10:24 PM Susan Hastings <[email protected]> 
>>> wrote:
>>> Hi Bill, have you tried using the same USB cord on a different port on your 
>>> MacBook Air. And, failing that, using a different USB cord. Cheers, Susan.
>>> 
>>> Sent from my iPad
>>> 
>>> > On 17 Feb 2019, at 5:10 pm, Juliet Kitson <[email protected]> wrote:
>>> > 
>>> > Hello Guru's
>>> > I have just tried to connect my Nikon D3200 to my Macbook air but it does 
>>> > not  see it so I connected a card reader does not see this either.It used 
>>> > to work a couple of software versions ago.
>>> > Software Version 10.14.2 any clues.
>>> > Regards Bill 
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