Hi,
Thanks for getting back to me with these additional details!
Based on this set of lines in the dmesg output the system is unable to set the enclosure to either the U1 or U2 low power states ( defaulting to U0 full power ).
[ 3947.240217] usb 4-1: Enable of device-initiated U1 failed.
[ 3947.241930] usb 4-1: Enable of device-initiated U2 failed.
[ 3947.303202] usb 4-1: Enable of device-initiated U1 failed.
[ 3947.304837] usb 4-1: Enable of device-initiated U2 failed.
After smartctl runs the USB connection is being dropped, that is definitely not the expected behavior but could be caused by improperly formatted commands. To help rule out a compilation error could you try the SmartMonTools static linked pre-compiled binaries here ( https://1002-105252244-gh.circle-artifacts.com/0/builds/smartmontools-linux-x86_64-static-7.2-r5076.tar.gz ) and let me know if this is similarly affected?
Additionally, when booting to the external enclosure, is this on the same computer using the same USB port? Also does the external drive have Ubuntu 20.04 installed with the latest updates?
I am not 100% sure if dmesg will capture the initial USB connection details for the operating system booted from the external enclosure but we can quickly search the dmesg output for ‘U1 failed’ and ‘U2 failed’ using the following:
dmesg | grep -Ei “U[12] failed”
Running smartctl could cause the active SSD to disconnect when booted from the enclosure which has the potential to cause data loss to any files not fully written to the drive, I would recommend not running smartctl while booted from the external unless it passes successfully on the internal operating system without taking the USB enclosure offline.
Thank you,
Pat
Plugable Technology
support@plugable.com