Some SD Cards Not Working Properly With 2021 14 and 16-Inch MacBook Pros

The SD card reader slot on the new 14 and 16-inch MacBook Pro models is not functioning as expected with some SD cards, according to multiple reports on the MacRumors forums.

In a long complaint thread, MacRumors readers have detailed the issues that they're having with some SD cards, and there seems to be little consistency between reports and affected SD cards. Some SD cards crash and can't be accessed, while some have unusually slow transfer speeds. MacRumors reader Wildc^t explains the issue:

Same issues with 14" M1 Pro. Just seems to be super flakey and inconsistent. Half the time it'll recognize the card successfully (though it takes anywhere from 30s to 1m) and half the time it'll throw an error. These are all Sandisk Ultra cards, both XC and HC, that were formatted in my camera. I tried reformatting them w/ the MBP and that didn't seem to make a difference. All my cards work as expected in my 3 other USB card readers.

In some situations, there's just an error message when attempting to use the SD card, sometimes Finder crashes, and sometimes the SD card takes many minutes to be accesible. From MacRumors reader 2Stepfan:

It's very frustrating. I was hoping that import from SD card including preview of images would be quick on my new 14" MBP. I have a fairly new 64GB SD card which had been working fine. But Photos on the MBP using the internal SD card slot takes minutes to show photos and sometimes crashes half way through. Sometimes the Finder crashes too.

Based on the thread, formatting does not appear to be the issue, though it could be a factor. There also does not seem to be a common thread between which cards work and which do not, but multiple users have reported that using an SD card reader over USB-C works when the SD card slot does not. From MacRumors reader wilberforce:

I tried many cards, and could find no pattern of brand, size, type, format, age. Seems to be completely random. The only thing that is consistent is that if a card works, it always works, and if a card does not work properly it never works properly. Reformatting, even to all other possible formats, makes no difference. Sandisk, Sony, Samsung, 16GB, 32GB, 64GB, 128GB, 256GB, UHS-I, UHS-II, micro-SD, FAT32, exFAT, makes no difference. 100% of my cards work perfectly via a dongle.

Some readers who have contacted Apple have been told that the company is aware of the issue and that a fix is coming in a future software update, but it is not clear if this is a hardware issue or a software issue. Some users who had problems replaced their MacBook Pro and did not continue to have issues, so it's not known exactly what might be going on.

Many of the reports are about older SD cards and there may be a particular issue with some 128GB cards, but for the most part, complaints are all over the place in terms of SD card brand, speed, and capacity.

One user reported that the macOS Monterey 12.1 beta had fixed the issue, but another person on Reddit said that the most recent beta did not address it, so we also don't know if macOS Monterey 12.1 might have a fix.

Those affected who are unable to use their SD cards with the SD card slot can access their cards by using an SD card reader dongle, which is not an ideal solution but at least provides a way to get SD card content onto an M1 Pro or M1 Max Mac.