Title: M5 MacBook built-in SD reader stopped detecting cards inserted after boot (macOS 26.7.1)
When it started: Saturday, October 24, 2026. Hot-plugging worked that morning and stopped working later the same day.
What I'm seeing:
- If I start macOS first and then insert the SD card, the card isn't detected. This worked in the morning.
- If I insert the SD card first and then start macOS, the card is detected and works normally.
- If I eject the card and insert it again, the system no longer detects it until I restart.
Test results:
- Normal mode, card inserted before startup: detected
- Normal mode, card inserted after startup: NOT detected
- Safe Mode, card inserted before startup: detected
- Safe Mode, card inserted after startup: NOT detected
I get the same result in Safe Mode, so it isn't a third-party extension. The reader only initializes if a card is already in the slot at boot.
What I've tried:
- Several cards, all of which work in other devices
- Updating to macOS 26.7.1 (build 25G241) and restarting
- Safe Mode, as shown above
System Information: the built-in SD card reader is listed (Vendor 0x17a0, Device 0x9755), but Link Width and Link Speed both show "Off" when I insert a card after startup.
I've found similar reports on M1, M2 and M3 Macs going back to Sonoma, but no fix:
- M2 Max, only detects SD card when rebooted with it inserted: https://www.reddit.com/r/applehelp/comments/1hsreio/
- 2021 MacBook Pro, detected once, not after eject: https://www.reddit.com/r/applehelp/comments/1wkc1cv/
- M1 Max, same 0x17a0/0x9755 reader, only works if inserted at boot: SD Card Reader Only Works if Inserted at … - Apple Community
Has anyone gotten hot-plugging working again on Tahoe 26.7? Is this a known bug, or is my logic board on the way out?
