I used Rufus 3.8.1580 (Portable) to create a bootable drive on a Kingston DataTraveler 16GB using elementaryos-5.0-stable.20181016.iso. I included a Persistent partition size of 4GB, file system FAT32, Cluster 8192 bytes. Both Rufus and the iso files were run/copied from the hard drive of a Dell Latitude E6520 with 8G ram and Intel Core i5-2520M @ 2.50Gz, Intel HD Graphics 3000 running Windows 7.
I get the following response when booting to the USB:
No Caching mode page found Assuming drive cache: write through BusyBox v1.27.2 (Ubuntu 1:1.27.3-2ubuntu3) built-in shell (ash) Enter 'help' for a list of build-in commands.
(initramts) mount: mounting /cow on /root failed: Invalid argument overlay mount failed