This is a basic question, but I did not uncover the answer with a search of the manual & these forums. I’m not saying the answer is not in either place; I just couldn’t find it.
The question: Does the host computer need to remain attached once printing has begun?
Yes, never change the conncetions during a print:
.) Don’t disconnect or connect the USB calble during a print or let your PC go to standby / rebott / shutdown or startup.
.) Don’t remove or insert the SD Card during a print.
Each change on the USB port may trigger the reset pin of the printer board, which means your ongoing print is ruined…
Mini does not have a SD card slot unless someone has added the LCD read out / controller. The rest is correct like he says never disconnect or allow the computer to go into power saving. What I do on my computer is turn off the internet or wireless connection, you don’t want an update while your printing!