I clicked the help button on a notebook that was running an evaluation and it closed it, not sure why, but it had been running about two hours, before i clicked the help button. Im new to mathematica 12 but used the 5.2 for years, Im on day one of the trial verson. I suppose I wont click that help button anytime soon. I was at about 98 gigabytes of 128 gigabytes on the ram use, and no page files yet. Got a windows 10, 2 terabyte ssd, dual xeon workstation.