Xubuntu live usb persistence - how to?

If your settings and files are not saved when you reboot, you do not have persistence enabled.

You can either make a new Flash drive. This may be easiest as there are graphical tools to do this for you ("install" the iso to the flash drive and enable persistence).

See: https://wiki.ubuntu.com/LiveUsbPendrivePersistent#Live_USB_creator_.28GUI-based.29

Alternately you can manually enable persistence. You can do this either by making a file or partition named "casper-rw". I think making a file would be easiest.

First, mount the flash drive at say /mnt

sudo mount /dev/sda1 /mnt

then make a file, change the count to increase the size:

dd if=/dev/zero of=/mnt/casper-rw bs=1M count=128

mkfs.ext4 /mnt/casper-rw

Then reboot, at the boot screen add the work "persistent" to the boot options.

See https://help.ubuntu.com/community/LiveCD/Persistence#Using_a_Loopback_File for details.