https://www.youtube.com/watch?v=n8JJW1xEwPI

Look this

By crashing I assume you mean one instance randomly closes (as opposed to being brought back to offline character select screen).
How much RAM do you have and how much is utilised with one instance running?
What GPU do you have?
Have you set graphics settings lower, set an FPS cap and running in windowed mode with the secondary account running the smallest resolution?




Outdated guide and doesn't provide answers to someone's secondary instance crashing.

fixed it
just i try too load all champ too fast and got crash

is this still working? when i load the 2nd bliz launcher it states playing now and i cannot load another game