NEF file extension not recognized in Sequoia v 15.8

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J22Indy Author

Level 1

8 points

NEF file extension not recognized in Sequoia v 15.8

NEF File extension not recognized in Sequoia v 15.8

Posted on Sep 17, 2026 10:30 AM

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Answer 1

Sep 18, 2026 6:01 AM in response to J22Indy

One, taking a long time for a file move is not the same as Finder not recognizing NEF files.

Just to be absolutely clear, you are moving a file from one folder to another in Finder and not moving the file in ON1? Is ON1 open at the same time with the same folder open? Which model MacBook Air are you using? Which version of ON1?

FWIW, I have no issues with file moving or copying Nikon NEF files in the latest version of ON1 and macOS Golden Gate. Also, I never had issues when I was running what was the current version of ON1 at the time I was running macOS Sequoia.

Without additional info, you can try a Disk First Aid in Disk Utility on the volume(s) that you are working with. There may be some directory corruption.

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Answer 2

J22Indy Author

Level 1

8 points

Sep 18, 2026 6:25 AM in response to woodmeister50

Thank you for your reply; I appreciate that functioning of Finder is different than On1 and am happy to provide the following:

My MacBook Air is the last with Intel chips, 1.1Ghz Quad i5 and that is (presumably) why I'm stuck at macOS Sequoia v15.8... which I just updated to.

I've just returned from Egypt with well over 2000 images on my Nikon Z50 and I always shoot both JPG and RAW (NEF), then sort the files into separate folders for processing.

My speed issue just occurred after the update and only affects moving files from a base "dump" folder (a copy from the Nikon's flash) to a \NEF folder on the internal flash drive; i.e., C:\workingNEF. To check that it is a MacBook Air issue I'm using an older MacBook Pro 13" with macOS 11.7.11 and a SanDisk 2Tb external flash and I am not having any issues with moving files.

I only mentioned using On1 to clarify that this app can see and process .NEF files that have been moved by other means... but On1 is not loaded when having the speed issue in Finder.

I hope this helps as I'd really like to update to an M5 version of the MacBook Air but I just turned 80 and that would really stress the budget.

Thanks.

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Answer 3

J22Indy Author

Level 1

8 points

Sep 17, 2026 11:53 AM in response to J22Indy

To clarify, this involves moving files in Finder; it appears my On1 program is still functioning, but it takes minutes to move a single file on the same internal drive.

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