Are you installing to "Disk 0 Apple HDD..."? Or are you installing to the partition that is 209 MB? Could you take a screen shot of "Disk utility"View attachment 2159086
View attachment 2159087View attachment 2159088View attachment 2159089View attachment 2159090
After I remove the USB and restart the computer. When loading, I hold the button to select the boot - only the Macintosh disk is on the screen for selection/
I install not on Flash