Is the USB drive an external hard drive or a USB flash drive?
Please check to see if any of the following items apply to your situation:
1. Please make sure that the USB drive is connected to a USB 2.0 or 3.0 port, connected to a USB 1.0 port is not supported.
2. Please make sure that the boot partition on the USB drive is aligned to 4k sectors. If the partitions on a SSD are not properly 4k aligned, this will cause a significant drop in performance on the partitions.
Please check to see if any of the following items apply to your situation:
1. Please make sure that the USB drive is connected to a USB 2.0 or 3.0 port, connected to a USB 1.0 port is not supported.
2. Please make sure that the boot partition on the USB drive is aligned to 4k sectors. If the partitions on a SSD are not properly 4k aligned, this will cause a significant drop in performance on the partitions.