Mac Book Pro: External Hard Drive Blinks 10 times but then stops working

oski wrote:

tried different ports on my USB C adapter.

If you are using an adapter, then try connecting the drive directly to the laptop, or try another adapter. Also try another USB-C port on the laptop, especially one on the other side.

Is this external Toshiba drive a Hard Drive or an SSD?

Check if the physical drive appears in Disk Utility. Within Disk Utility you may need to click "View" and select "Show All Devices" before the physical drives appear on the left pane of Disk Utility. If it appears, then try running First Aid on the physical drive, then run First Aid on the Container (you may need to "mount" or unlock it first if it is encrypted).

Does this drive have its own dedicated power adapter? Or do you have a powered USB3 hub you can use?

It is possible you may need to give that drive permission to connect to the M-series laptop. I personally prefer to configure the "Allow accessories to connect" Privacy & Security System Setting to "Always when unlocked" since you may not always see the pop-up notification asking you to confirm if it is Ok to access the external device.

If your Mac asks you to allow an accessory to connect - Apple Support

oski wrote:

The odd thing is this Toshiba HD always just came to life when plugged in. HD Model shown here: https://www.amazon.com/Toshiba-Canvio-Basics-Portable-External/dp/B0BQX6NNVC?th=1

I am using a USB adapter because my mac only takes USB C and the Toshiba came with the old fashioned (USB B?) cord. I purchased the Toshiba HD in July 2024. It does not have a dedicated power line, but always functioned properly before.

I never liked those USB3 micro ports. They break so easily and can be difficult to connect a cable causing the port to weaken over time. It is possible the USB connector on the back of the drive is damaged, perhaps with broken solder joints. It could easily explain the issue.

Any drive or device can fail at any time. However, you must be extremely careful buying them online especially from Amazon and other sites which allow anyone to participate in their marketplace. A large number of Amazon marketplace sellers are scammers selling inferior & dangerous products including used items & fake items. I have seen some good name brand products such as Toshiba being sold as new, but the sellers have replaced the internals with junk.

I went into Applications - Utilities - Disk Utilities and even on the left column my Mac is only "seeing" Macintosh HD. It's as if the external HD is not being seen at all.

Definitely try "Show All Devices" within Disk Utility.

The only other computer I have is a Dell desktop running Windows 11. I wonder if I plug the Toshiba HD into the Dell (which I've never done) and reformat it in some way, can I make it functional on my mac. I am wary of plugging it into a PC that might want to format just for PC,

Windows won't automatically format a drive. I'm not even sure if Windows will prompt you to format it if it has an unknown filesystem. If you launch Disk Management, you should be able to see if the physical drive is shown along with its partitions, although I'm not sure how reliable Disk Management is with Win10/11....I had issues seeing a drive recently where it was there, then I did something then could not see the physical drive again. This is the same thing I'm trying to help you with on macOS by configuring Disk Utility to "Show All Devices" since it defaults to hiding the physical drive from view.

Even if you format the drive with a Windows only file system the Mac will at least be able to read the contents. You can always erase the drive on macOS using Disk Utility. From your description it sounds like some sort of hardware issue.....drive, cable, adapter, or power issue.

Another option on macOS is to run DriveDx (free trial period) to check the health of the external drive, but this will require installing a special USB driver. If the drive is physically seen, then we can verify its health. Post the complete DriveDx text report here using the "Additional Text" icon which looks like a piece of paper on the forum editing window toolbar. GSmartControl (free, open source) is a similar utility for Windows (there is a portable version of GSmartControl that can be run from the Downloads folder without installing anything). Again, post the complete health report here. I think there is a "View Output" and "Save As..." options which will provide you with the whole health text report.

oski wrote:

I believe it has a one year warranty and I purchased in July, 2024. I'll find out tomorrow when I speak with them. Incidentally I plugged the external HD into our Dell Desktop to see how it would react. It did the same thing: one quick blink, then 10 blinks and off, not recognized in the PC Control Panel, so I think it's not my Mac that has a problem. Thanks for your input.

Sounds like a hardware issue with the drive, or possibly the cable, or the adapter if the adapter is also being used with the Dell.

OK, that's not a drive that requires 12 volt power.

But you need an adapter that passes the full amount of power through to the drive, which come inferior adapters do not do properly.

a 2TB Toshiba you have had for a few years is very likely to be a Rotating Magnetic drive.

If that is correct, it will need the power supply connected to get enough 12 Volt POWER to spin up the drive. USB can not possibly provide enough power for most rotating magnetic drives.

Drive-makers are typically trying to answer only ONE question:

is this drive still under warranty? ...

... and if it is, to send you a replacement unit.

I have found them to be completely not interested in the nuances of whether a drive will mount or perform under any circumstances.