External USB disk visible only after reboot

Hi,

I've a T640 with Windows Server 2019.
I use external USB disks for backup, rotated daily.
Sometimes the external disks are not recognized: they don't show up in Device Manager.
As soon as I reboot the server, the disk is correctly recognized.
Some day later, after I change the disk, the new disk is no longer recognized.
Suspecting an hardware issue on the USB port/controller, I installed a new USB adapter card, but the issue persist.
Disks work correctly on another PC.

While the server is rebooting it goes Blue Screen and then restart correctly.

Latest Blue Screen error was 0x00000139 (KERNEL_SECURITY_CHECK_FAILURE).

DSIM and SFC show no errors.

Time for a new server??