Why is SD card file transfer SO SLOW on new Macbook Pro?

Some Apple techs are just clueless, and companies always love pointing fingers at other companies whenever possible (sometimes justified, but most times it is an excuse to get the person to leave). An Apple Authorized Service Provider may be more wiling to assist you especially if the AASP also deals with other hardware or sells third party peripherals for the Mac. macOS includes native built-in exFAT file system support so it is supported.

It appears either the SD Card may be bad due to the errors you mentioned or perhaps the data has just become corrupted which can easily cause slow transfers. If you have your data backed up, then try erasing the SD card using Disk Utility and test the transfer speed again. Test transfers to and from your internal drive and SD card so you eliminate any possible issues with your USB drive. Transfers to and from the internal drive should be as fast as your SD card can transfer.

zschaeffer wrote:

I bought a brand new Macbook Pro last week. Today I am trying to transfer files from my SD card (SanDisk Extreme, ExFAT, inserted directly into the laptop) to my external hard drive (LaCie, ExFAT, USB-C to 3.1 Micro USB), a process I've done literally hundreds of times on my old machine with no issues.

The files process and transfer at a snails pace, and the first file of each batch I try to move gives me an error that the file is corrupt. After accepting the error, none of the files transfer. If I transfer that one "bad" file on its own, it will eventually transfer with no issues (just slow).

I spent an hour on the phone with Apple support and they are telling me the issue is with my SD card and my hard drive—that ExFAT is an unsupported format and I need to reformat the card and the drive.

However, I just used my old machine and completed the transfer with absolutely no issues. The only thing that's changed is the new computer. What's going on here?

If its relevant, I am running OS Monterey.

Did you try moving to a faster card...(?)

• UHS‑II  (MacBook Pro introduced in 2021, iMac introduced in 2020, and iMac Pro only)

https://support.apple.com/en-us/HT204384