SD Card reader stops working until reboot

iMac (Retina 5K, 27-inch, Late 2015)

I've seen people post with the same issue and was wondering if anyone has found a fix for this issue.

The card reader starts at boot up, but eventually stops recognizing cards when they're inserted until you reboot.

Thanks!

iMac 27″, macOS 12.6

Posted on May 26, 2023 4:47 AM

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SD Card Reader Only Works if Inserted at Boot (M1 Max, macOS Sequoia 15.3.1) Hello everyone, I’m encountering a persistent issue with the built-in SD card reader on my MacBook Pro (M1 Max), running macOS Sequoia 15.3.1. I’d greatly appreciate any insights or advice from the community. Issue Overview If I start or reboot my Mac with an SD card already inserted, the card mounts correctly. In System Information, the reader shows: Link Width: x1 Link Speed: 5.0 GT/s Vendor ID: 0x17a0 (Genesys Logic) Device ID: 0x9755 This confirms the card reader is recognized and functioning at that moment. However, when I remove the SD card and reinsert it later (while the system is running), it fails to appear in Disk Utility or via diskutil list in Terminal. At that point, System Information typically displays: Link Width: Off Link Speed: Off indicating the SD card reader is effectively powered down or not reinitializing. What I’ve Tried Using multiple SD cards (FAT32, various sizes and brands) — same result. Disk Utility / diskutil list — after reinsertion, the card does not appear. Resetting NVRAM/PRAM and SMC (where applicable) — no change. Safe Mode — tested to see if any third-party extensions might interfere, but the behavior persists. Checking system logs (Console) — no new entries when re-inserting the card, suggesting the hot-insertion event isn’t recognized. Notes & Additional Details The SD card reader is identified as Genesys Logic (0x17a0, 0x9755). When the card is recognized (only at boot), I can read/write with no performance or corruption issues. Removing it and re-inserting it afterward never triggers a mount—only a reboot fixes it. Request for Help Has anyone experienced a similar hot-plug issue with Genesys Logic-based SD card readers on M1 Macs? Are there any workarounds or additional steps I might try to ensure the reader properly re-establishes a link after card removal? Could there be a known firmware patch or macOS update that addresses this? I rely on my SD card workflow daily, and restarting every time I switch cards is quite disruptive. Any suggestions would be hugely appreciated! Thank you in advance for your assistance. I’m hoping this post can also help anyone else facing a similar situation.
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SD card reader stops working until a reboot My SD card reader will stop working until I do a reboot and then it works again. All of the SD cards are readable for quite some time, then the reader stops and I can't read any card until I reboot the Mac.
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6 replies

fbrandt

Level 1

16 points

Feb 21, 2024 12:53 PM in response to BDAqua

Could you please explain what is mA?

BDAqua

Level 10

250,181 points

Feb 21, 2024 1:44 PM in response to fbrandt

milli Amperes...

tbirdvet

Level 6

16,819 points

May 26, 2023 5:56 AM in response to KoreaDickie

I had the same issue but started to work after I updated to the next OS revision.

Feb 19, 2024 9:56 AM in response to KoreaDickie

I had the same issue. It was solved when I brought it to the Apple store and they reloaded the firmware.

BDAqua

Level 10

250,181 points

May 26, 2023 5:52 AM in response to KoreaDickie

Many times it's due to drawing too many mA on the USB Bus.

tbirdvet

Level 6

16,819 points

Feb 21, 2024 4:03 PM in response to fbrandt

That stands for milliamp or current draw although an SD card would draw very little current.

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SD Card reader stops working until reboot