Quicktime Screen Recording Crashes

Hi. I’m trying to do a screen recording of ALK2 but QT crashes everytime I try to do a screen recording when ALK2 is on (not even running, just on). All functions of QT work perfectly otherwise and I seem to be able to do a new movie recording w QT if ALK2 is on, just not a screen recording

Apple MacBook Pro Retina Core i7 2.4Ghz 8GB RAM 768GB SSD os 10.11.6