InDesign Crashes with Dual Monitor

Hello! My InDesign keeps locking up my computer whenever it is hooked up to a dual monitor. My external screen goes green and my Mac screen goes black. I've spent countless hours trying to figure this out with Apple, but they're telling me it's a software program. I've uninstalled and re-installed InDesign on the computer and it keeps happening. Only when I'm in InDesign and have a dual monitor hooked up. Has anyone found a solution to fix this? I'm at my magazine deadline and I keep losing my work or have to work off one monitor!