I play vanilla Minecraft off of a portable HDD. Java is on the HDD with the game and I launch with a batch file as recommended on the official Wiki.

I play vanilla Minecraft off of a portable HDD. Java is on the HDD with the game and I launch with a batch file as recommended on the official Wiki.

Steps:
1 - Launch launcher
2 - Click download and Play
3 - After libraries are downloaded I play
4 - After a couple of minutes game exits on its own