Corrupted SSD / Partition map (?)

Select the physical SSD on the left pane of Disk Utility and click the "Erase" tab on the right pane to erase the whole physical drive as GUID partition and MacOS Extended (Journaled). If this does not work, then you will need to unmount all volumes from the SSD, then use the command line to write zeroes to the beginning of the SSD to destroy the partition table. Then you should be able to use the Disk Utility GUI to erase the physical drive.

For example if the physical SSD is "disk2", then you can use the following commands (of course replace "disk2" in the following examples with the correct drive identifier for your external physical SSD):

diskutil  unmountDisk  disk2

dd  if=/dev/zero  of=/dev/disk2  bs=100m  count=10

If none of this works, then it may indicate you have a hardware issue with the SSD, the enclosure/adapter for the SSD, or the USB cable. You can attempt to check the health of the external SSD by running DriveDx if you have a full macOS boot drive. You will need to install a special USB driver in order to attempt to access the health information on the external SSD, but some USB controllers on USB Adapters/Enclosures will not allow the necessary communication even with the special USB driver. Post the full DriveDx report here using the "Additional Text" icon which looks like a piece of paper.

If you don't have a full macOS boot drive in order to run DriveDx, then I can provide instructions for creating & using a bootable Linux USB stick to check the health of the SSD.

Within DriveDx, select the SSD on the left pane and click the "Save Report" button on the top right side of the app. Then copy & paste the whole report here using the "Additional Text" icon which looks like a piece of paper at the bottom of the forum's editing window.

From the partial report this SSD has had some UDMA CRC Errors which usually indicates an issue with the cable. Unfortunately it is impossible to tell if this is due to the internal cable if the SSD was installed internally, or whether it is with the external USB Adapter since this attribute does not record any date/times. If you are only using this SSD externally now you can check this value again to see if it has increased (or check it while installed internally). You will first need a baseline on value on which ever port/cable you use, then run the SSD only from that port/cable to see if the value increases.

See if you can run the SSD's internal short self-diagnostic from DriveDx.

I'm glad you provided the full report because I'm not certain there are any CRC errors. It may be that the DriveDx GUI is misrepresenting this information or the utility may not be fully knowledgeable about how the health information is stored on this particular model SSD.

I want you to use the command line to get another health report from the SSD since the DriveDx GUI may be corrupting the report a bit. You will need to get the drive identifier for the physical SSD which you can get from DriveDX, Disk Utility, or the Apple System Profiler. In the DriveDx report you shared the drive identifier is listed as "disk2", but this may change the next time you boot the laptop or the next time you connect the SSD externally so you will need to get the current drive identifier when you run the Terminal commands.

The easiest way to enter the command is by first typing "sudo " into the Terminal. Then drag & drop the DriveDx app from the Finder window onto the open Terminal window so the correct path is automatically filled in. Then press the "Delete" key to delete the trailing space, then finish typing "Resources/smartctl -a /dev/diskX". You need to replace "diskX" with the correct drive identifier for the SSD at the time you are executing this command. So the final command will look something like this:

sudo  /Users/hwtech/Downloads/DriveDx.app/Content/Resources/smartctl  -a  /dev/disk2

You will be prompted for your password. Nothing will be displayed on the screen as you type the password. Press the "Return" key to submit the password.

You can also run the SSD's long/extended self-diagnostic during the DriveDx trial period by using the command line by modifying the above command by removing the "-a" option and replacing it with "-t long". The output will provide an estimate for how long the test may take. You can check the results using the DriveDx GUI interface. The command should look something like this:

sudo  /Users/hwtech/Downloads/DriveDx.app/Content/Resources/smartctl  -t  long  /dev/disk2

You may want to check to see if there are any firmware updates for your SSD. This may be hard to do if Kingston is only providing a Windows only option for updating the SSD's firmware. The SSD's current firmware revision is listed in DriveDx.

I can provide instructions for using a Linux boot disk to try to perform a hardware secure erase using the SSD's built-in hardware secure erase feature to reset the SSD to factory defaults which can sometimes fix odd issues if the SSD gets into a weird state. This is best done with the SSD connected to an internal SATA controller.