I’ve also been seeing this crash since this morning, I’m not using the AddChildActor node but I am using several Child Actor Components and the new child actor template functionality introduced in 4.14. Same error caused by Casts.cpp. Moving the problematic blueprints out of the folder, opening the project, then moving them in seems to be a workaround for now, but the crash just happened again when I tried to open the project and I can’t seem to figure out why. Any help would be appreciated!