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Question

Problem importing images with FAT32 CF/SD

Forum|Forum|6 days ago
January 28, 2026
5 replies
104 views

This has been discussed extensively, but I haven't found a satisfactory solution.

Lightroom is extremely slow when checking for duplicates importing new images. I have a 2009 iMac that performs this process 10 times faster than my Mac Studio M4 with a 64GB RAM and 2TB SSD.

CF (or SD) card containing the camera RAW files is formatted in FAT32 (the format used by the camera itself). I format the CF card to Mac OS Extended format, and save the folder with RAWs in it, the duplicate check is incredibly fast (just like on my iMac). The problem is that I can't use a CF card with that format in my camera.

Someone suggested, in another post, an intermediate solution, which is to download the images to the computer and import them directly from there, but this involves more steps and ultimately results in a slower import from the card.

I'd like to know why a 15-year-old computer performs this function much faster than a recent, super-powerful, and super-expensive computer.

KR Seals

Community Expert

That’s just the nature of the FAT32 format. I have done tests on external SSDs formatted in FAT32 and they are far slower than drives formatted in the native OS, either Windows or Mac OS.

Ken Seals - Nikon Z 9, Z 8, 14mm-800mm. Computer Win 11 Pro, I7-14700K, 64GB, RTX3070TI. Travel machine: 2021 MacBook Pro M1 MAX 64GB. All Adobe apps.

RMMM2Author

Participating Frequently

Yes, I'm aware of the limitations of the FAT32 system, but it still amazes me how a late 2012 iMac with 24GB and Catalina is able to perform a task as basic as a duplicate check 10 times faster than a 2025 Mac Studio M4 with 64GB of RAM and a 2TB SSD.

GoldingD

Legend

When you format the card for the camera, do you format that in camera? I would generally not recommend formatting it in computer. Some old info in the back of my head that I do not have a reference to, might be urban myth.

Also, Apparently when you import within LrC with it in FAT32, it is extremely slow, but what about simply copying photos outside of LrC, using Finder? That is copy the files without LrC, simply using Finder to copy them to your hard drive in the desired folder. Is that also slow?

Agggggh, this new community sucks, just noticed the very obvious more at the bottom. I may have created an unwanted reply that was already posted. .

RMMM2Author

Participating Frequently

Yes, I always format the card in the camera.

Transferring the photos to a folder on the computer is relatively quick, as quick as the card speed. Then, importing and checking for duplicates is very fast... but in this case, we need two steps: first, transferring the images to a folder, and then the import itself.

With an iMac (or with the card formatted in Mac OS Plus), those two steps are combined into one, and much faster.

GoldingD

Legend

So, not a problem with the card, not a problem with the MACOS, something odd going on during import, preview creation? metadata mods? rights? (not likely)

One odd procedure to attempt. This one normally for when import fails completely, but, a modified workflow as a test/diagnostic/fix, that might accomplish absolutely

Take a few new images
In LrC, select the images
Over on the right, for destination, change the destination to a different folder.
Choose Copy,
Try the import
If that looked better, try again, but with the destination changed back to desired.

Wondering if the catalog has an issue with destination location

Ian Lyons

Community Expert

Make sure that you’ve selected the version of your CF card that’s listed under ‘Files’ rather than ‘Devices’. ‘Files’ is the default for card import.

RMMM2Author

Participating Frequently

I know, is listed under “Files”. Thanks!

D

dj_paige

Legend

I don’t think it has anything to do with FAT32, and so please don’t jump to conclusions. I think it is more likely that there is some hardware malfunction on your Mac Studio, could be the card reader (or USB port).

JohanElzenga

Community Expert

I disagree. He said “I format the CF card to Mac OS Extended format, and save the folder with RAWs in it, the duplicate check is incredibly fast (just like on my iMac)”, so that rules out the card reader or the cable in my opinion.

Reading FAT32 on a Mac is slower than reading a native Mac format, and it is possible that newer MacOS versions make a more thorough check that slows this down compared to an old Mac running an older version of MacOS. I never timed it and I do not have an old Mac to do that now, but I do not have the impression that my SD cards are really 10x slower than in the past.

-- Johan W. Elzenga

JohanElzenga

Community Expert

If you quantify ‘extremely slow’, then other people can compare that to their computer. My M1 Max MacBook Pro does not seem to be particularly slow importing from SD cards, but perhaps you expect an entirely different speed than I do.

-- Johan W. Elzenga

RMMM2Author

Participating Frequently

You’re right. To give you some specific details, here's my setup:

- Sandisk 64GB 120MB/s CF card

- Lexar USB 3.0 card reader

- Mac Studio M4 / 64GB RAM / 2TB SSD (Sequoia 15.7.3)

I'm referring to checking for duplicate images in Lightroom Classic desktop version.

The card contains 960 RAW files already imported into the Lightroom catalog. The software checks for duplicate images, scans the card, and displays the new images. The check takes the following time:

- Card formatted in FAT32: 5’26”
- Card formatted in Mac OS Extended: 0’31”seconds (approximately the same time it takes a 2009 iMac with the card formatted in FAT32)

I format the card in Mac OS Extended and add the same images, the problem is that the card with that file system doesn't work in my camera (Canon EOS 5D Mark IV).

I'm afraid Apple/Adobe hasn't done things right with Sequoia. What operating system do you have on your Macbook Pro M1 Max?

JohanElzenga

Community Expert

So we are not talking about the actual importing of images, but just checking and displaying them? I know that there is an issue with that, but 5’26” does sound slow indeed. I’ll try this on my Mac a little later. I use MacOS 26.

-- Johan W. Elzenga

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