"Start Xvfb server and open xmessage window. Thread safe." import threading from easyprocess import EasyProcess from pyvirtualdisplay.smartdisplay import SmartDisplay def thread_function(index): # manage_global_env=False is thread safe with SmartDisplay(manage_global_env=False) as disp: cmd = ["xmessage", str(index)] # disp.new_display_var should be used for new processes # disp.env() copies global os.environ and adds disp.new_display_var with EasyProcess(cmd, env=disp.env()): img = disp.waitgrab() img.save("xmessage{}.png".format(index)) t1 = threading.Thread(target=thread_function, args=(1,)) t2 = threading.Thread(target=thread_function, args=(2,)) t1.start() t2.start() t1.join() t2.join()