Enable Dev branch, return to v 1.48 (about 300 Mo to download);
check for Arma 3 integrity files from Steam : 1 file corrupted then corrected.
Launch Arma with the launcher
verify no addon enabled
edit on stratis map. place one unit or one group
preview (or record then play)
See video on you tube https://www.youtube.com/watch?v=zoENMZl7sbw&feature=youtu.be