Macbook Air M2 stopped recognizing external hard drive

Return it, it is a voltage Issue on the Motherboard.

I had 2 repair attempts made by apple itself, based on my AppleCare+.

And now they refund me the money for the 2 year old device and my AppleCare+.

On the first repair they replaced the USB Flex Cables which connect mainboard with ports - no change.

On the second repair they sent the device back saying it works "NORMAL" - no change.

I had the exact same Issue, as did others:

External SSD Mounting Issue On M2 MacBook… - Apple Community

Send it in if you still have warranty.

I could buy a m3 with even more ram with the money I got returned, I will stay with my trusted M1 though.

[Edited by Moderator]

Congrats, you are free to upgrade your mac and depending where/when you bought it you can upgrade and also keep money.

at least thats how it works in EU for me.

Official apple support failed to diagnose, reproduce and fix the problem in their repair center, twice.

its neither a issue with ssd nor connection. Its the mainboard giving the wrong voltage to usb3 devices

Same here! For a few months it has been telling me "disk removed without first ejecting" erroneously, and then today, voila, nothing. Thumb drives, hard drives, nothing is recognized and there is no connection/power on the drives that are connected.

The thing that might have done something was that I used one of the usb-c ports to charge my macbook when I had forgotten a the power cord. Only for an hour or so, but it was working before that.

Have you found a solution yet? I cannot believe this hasn't been addressed by Apple

I would not use a thumb drive as a TM backup. Those drives are not that reliable. As far as your other issue your Mac should recognize your drives. If your drives are all SSD's I would be sure they are formatted to APFS, GUID. The OS prefers that format to function most reliability.

Angharad09 wrote:

Thanks tbirdvet. I know my Mac /should/ recognize the drives, and it did recognize them for a year before suddenly stopping.

What has recently changed on this newer Mac?

Did it coincide with a minor software update patch or an upgrade to a new major version of macOS?

Have you changed any external hardware which may have introduced a compatibility issue?

Did anything change in the home environment? New appliance, any odd electrical issues in the home where lights may go bright or dim at times?

Are you running any WD or Seagate proprietary software for these external drives?

Are you running any anti-virus apps, cleaning/optimizer apps, or third party security software?

Both of the drives still connect fine to my older Mac. They're formatted to Apple's specifications.

What partition type and file systems?

They've passed a "First Aid" inspection twice now.

Did you manually review the First Aid report by clicking "Show Details"? Unfortunately the First Aid summary results can not be trusted. I have personally seen the First Aid summary lie about the condition of the file system.

Within Disk Utility click "View" and select "Show All Devices" so that the physical drives and hidden Containers appear on the left pane of Disk Utility. Run First Aid on the physical drive and also run it on the hidden Container (it will scan all volumes within that container).

I'm 99.99% sure the problem is not with the drives but with the laptop. This is a known problem; I'm starting a new thread on it in the hopes that there may have been some recent progress in solving it.

I would start by checking the health of these external drives. Run DriveDx (free trial available) and post the complete DriveDx text reports here using the "Additional Text" icon which looks like a piece of paper so I can review them. You will need to install a special USB driver to attempt to access the health information of the external drives, however, even with this special driver, some external enclosures still won't allow the necessary communication to access the drive's health information.

Have you turn off the "Put hard disk to sleep when possible" option in the Battery System Settings? This option is only available (aka seen) when an external drive is actually connected now.

Have you tried disconnecting all other external devices in case one of them is causing a problem with these drives?

Are these drives connected directly to the computer? If so, have you tried connecting them to an independent power source such as their own power adapter or a powered USB3 hub in case it is a power related issue?

Try rotating the USB-C connector 180 degrees upside down when connecting the drive. Sometimes this will make things work better if the USB-C port or cable/adapter is half bad. Make sure to try each other USB-C port as well, especially one on the other side of the laptop if available.

Make sure to only connect a single drive while you are testing so that no other drive or device can interfere with it.

apparently, for this computer, resetting SMC happens automatically on restart, and resetting NVRAM is not applicable

There is no SMC for the Apple Silicon Macs....that was an Intel thing. Any necessary functions of the SMC chip needed on an Intel Mac has been incorporated into the security enclave chip and CPU....no one really knows which portions may have been incorporated.

Technically you can clear the NVRAM on the Apple Silicon Macs by using the command line. Within macOS you can use the following command:

sudo  nvram  -c

It will prompt you for your admin password. Nothing will appear on the screen as you type the password, so just press the "Return" key to submit the password. If there were no errors (it may complain about not being able to clear the computer name which is Ok), then reboot the Mac so that so that macOS will utilize the default NVRAM values. If you want to clear the NVRAM while booted into Recovery Mode, then omit the "sudo" part.

Avoid using any other options for the "nvram" to set any custom values since most of the older Intel values no longer apply and may temporarily "brick" an Apple Silicon Mac. I have personally used the command provided on one of my organization's Apple Silicon laptops. No negative side effects were noticed and it did fix a boot issue I had with the laptop.

Could I tag on one more question -- would you recommend for/against just getting a high-capacity SanDisk thumb drive and using that for Time Machine?

Absolutely not! USB sticks are very unreliable even from name brands, although the SanDisk USB sticks have been fairly reliable in the past...hard to say if they still are since a lot of WD products are declining in quality these days. Hard drives and SSDs actually include some error correction technology to help prevent data corruption unlike most USB sticks.