Yes, NEF, as mentioned, is the actually the Nikon RAW file You still have some options here,
1. re-instal the previous Apple OS Not the the best option IMHO
2. Download Nikon's dedicated Nikon software, Nikon Capture NX-D, you can find it here, https://downloadcenter.nikonimglib.com/en/products/162/Capture_NX-D.html Will handle your NEF files Nikon also has other software, Nikon ViewNX-i but is also having trouble with Catalina and is working on it right now
3. Adobe CC subscription which includes Lightroom and Photoshop $15 a month here in Australia but I think around $9.95 in USD IMHO, this your best option, albeit "not free"
lastly, make sure you have your NEF files backed up, they are your original files! ...........Gary
Firstly, welcome to Nikonians!
Yes, NEF, as mentioned, is the actually the Nikon RAW file
You still have some options here,
1. re-instal the previous Apple OS
Not the the best option IMHO
2. Download Nikon's dedicated Nikon software,
Nikon Capture NX-D,
you can find it here,
https://downloadcenter.nikonimglib.com/en/products/162/Capture_NX-D.html
Will handle your NEF files
Nikon also has other software, Nikon ViewNX-i but is also having trouble with Catalina and is working on it right now
3. Adobe CC subscription which includes Lightroom and Photoshop
$15 a month here in Australia but I think around $9.95 in USD
IMHO, this your best option, albeit "not free"
lastly, make sure you have your NEF files backed up, they are your original files!
...........Gary