SAMSUNG T7 Crashes iMac IMMEDIATELY it’s plugged in.

tim_dowd wrote:

Tried recovery mode started disk utility plugged in and BOOM crashed again. left it plugged in booted in recovery mode again same deal. it gets past the Apple logo but as soon as the progress bar shows it crashes within seconds

The easiest option would be to connect the drive to a Windows or Linux computer so you can erase it as it is unlikely those systems will have a problem since they don't normally understand the Apple APFS file system. Plus those operating systems tend to be better at working with unusual issues.

If you don't have access to a Windows (or Linux) system, then you can try booting into Single User Mode by using Command + S (Intel Mac only). Make sure to disconnect all other external devices from the Mac (keyboard & mouse are Ok to keep). Once booted into Single User Mode you will have a black screen with lots of text. You should have a command prompt of "#" showing. If you don't see this at the bottom of the screen, then press the "Return" key which should make the command prompt appear on a line with "#".

Once you have this, then connect the external drive. If the system doesn't crash, then enter the following command to get the drive identifier for the external drive:

diskutil  list  external  physical

It should display one drive (will also show that drives partitions & containers). The information on the first line is what we need as it will show the drive identifier in the form of "/dev/diskX". The "X" will be a number.....you may see "/dev/disk2". I'm just using "diskX" here because it is just an example/template...use the actual identifier listed from the output of the earlier command.

The next step is to unmount all volumes from that drive (make sure to use the identifier for your drive in place of "diskX" in my examples here):

diskutil  unmountDisk  diskX

If no errors, then you can write zeroes to the beginning the drive to destroy the partition table so the drive will appear blank:

dd  if=/dev/zero  of=/dev/diskX  bs=100m  count=10

Once completed, the external drive identified as "diskX" will appear blank to macOS. Just type restart the computer using the following command:

reboot

Once booted into macOS you should be able to use Disk Utility to erase the external drive. Assuming the partition table or file system was the reason for the crashes when connecting the external drive. If you still get the crashes, then you have some sort of hardware issue.

I'm assuming only the one external drive is connected to your Mac and no other external devices are connected except for a keyboard & mouse since this limits & minimizes the chance of destroying the data on the wrong drive or device (some external devices may appear as a drive).

As you can see using a Windows or Linux computer will be much easier, but the Single User command line will work if the problem is not due to a hardware issue. Just make sure to use the correct drive identifier for your external drive. Keep in mind the drive identifiers may change every time you connect a drive or reboot the computer. So always check & confirm you have the correct drive identifier each time.

Unless you are familiar with the command line, Single User Mode is not for you. Unless @jfrew meant Recovery Mode (Command + R) which is what Apple now considers "Single User Mode" when using the Terminal app as the traditional method is no longer available on newer Macs. Or Command + Option + R for Internet Recovery Mode. These special startup keys are only for Intel Macs. I would expect Disk Utility from Recovery Mode may be successful since it is a more limited environment than a normal boot. Perhaps even try booting into Safe Mode.

You can also try using a Windows or Linux system to erase the Samsung T7, then try reconnecting it to the Mac where you can use Disk Utility to erase the drive as GUID partition and whatever built-in macOS file system you want (not sure what file system the iPad may require).

jfrew wrote:

I'm quite comfortable with diskutil, fsck, etc., but I could use some guidance on specific tools and procedures in Monterey single-user mode; for example, how do I discover which /dev device has been assigned to the external disk.

Use:

diskutil  list

Depending on the version of macOS being used you can add the options "internal", "external" to filter between internal/external:

diskutil  list  external

Or "physical" to only list the physical devices and avoid listing the contents of the Containers:

diskutil  list  physical

The two can be combined (or use "internal"):

diskutil  list  external  physical

Just happen to have an old MacBook Pro that, thanks to Apple not supporting 3rd-party internal SSDs, is now running Linux. I was able to mount the T7 read-only and recover all of its contents, whew!

System details: MacBook Pro (Retina, 13", Early 2015), Linux Mint 21.1

Will follow up on whether I'm able to reformat the T7 and then access it on my Macs and iPad.

Same problem here. Samsung T7 2TB, been using it for almost 2 years on a MacBook Pro and a Mac Studio. Until yesterday it had never occurred to me to try connecting it to my iPad Pro; I did and it seemed to work OK (copied several GB from the T7 to the iPad; didn't explicitly copy anything to the T7.) Now the T7 immediately (as in, faster than I can run diskutil, etc.) crashes all my Macs (including an older one running Catalina). I can connect it to the iPad but it doesn't show up in the Files app.

FWIW, the T7 doesn't crash the Macs if they're in single-user mode.

System details:

• MacBook Pro (16" 2019), macOS 12.6.5
• Mac Studio (2022), macOS 12.6.5
• MacBook Pro (Retina, mid 2012), macOS 10.15.7
• iPad Pro (12.9" 5th gen), iPadOS 16.4.1 (a)

Thanks,

/Frew

@HWTech: I did indeed mean single-user mode. I tried safe mode and recovery mode; the T7 crashed both of them.

I'm quite comfortable with diskutil, fsck, etc., but I could use some guidance on specific tools and procedures in Monterey single-user mode; for example, how do I discover which /dev device has been assigned to the external disk.

Thanks,

/Frew

You can use the "mount" command to see if your external drive has any mounted volumes. It may not have any mounted volumes if the file system has a problem. If the external drive has a mounted volume, then it will show the drive identifier.

If the external drive has no mounted volumes, then you know the highest drive identifier being used with the internal drive & volumes. You can try running the "dd" command using the next highest drive identifier. If the external drive is connected & communicating properly, then this should give you access to the external drive.

You can also try using the full path for the "diskutil" command in case only a limited PATH is set:

/usr/sbin/diskutil