Since I migrated to a SSD my icons stopped getting shuffled on boot.
But here are some simple scripts for backing up xfce desktop icons. You will have to edit the resolution for your monitor.
I use crontab to run bakhourly.sh every hour (you can probably name this something better, this is a general script I use for other stuff also).
# back up 3 desktop icon positions
mv ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc.2 ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc.3
mv ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc.1 ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc.2
cp ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc.1
0 * * * * ./bakhourly.sh
Then I use recover_desktop.sh as an Application Autostart entry (in Session and Startup).
cp ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc.1 ~/.config/xfce4/desktop/icons.screen0-1904x1037.rc
Command to run recover_desktop.sh in Session and Startup
sh -c "sleep 21 && recover_desktop.sh"
Sometimes it works, sometimes it doesn't. So I usually just ran recover_desktop.sh manually after logging in then press F5 on the desktop.