USB Hangs Acronis in Memory

I created a bootable USB key fine yesterday but today, even after reboots, if I launch Acronis with either my Data USB stick or my Acronis bootable USB (both 4GB kingston drives) it will hang in memory until I unplug the USB drives. If I plug them in while Acronis is loaded, it will stop responding. How is this possible since yesterday I created a bootable USB fine?

Edit: It may be due to the Kingston Black 4GB USBs failing.