diff --git a/minerl/env/core.py b/minerl/env/core.py
index f0a77b3e4..36103e9d3 100644
--- a/minerl/env/core.py
+++ b/minerl/env/core.py
@@ -35,6 +35,7 @@
 import gym.envs.registration
 import gym.spaces
 import numpy as np
+from filelock import FileLock
 from lxml import etree
 from minerl.env import comms
 from minerl.env.comms import retry
@@ -47,6 +48,8 @@
 
 missions_dir = os.path.join(os.path.dirname(__file__), 'missions')
 
+launch_instance_lock = FileLock(os.path.join(os.path.dirname(__file__), 'env.lock'))
+
 
 class EnvException(Exception):
     """A special exception thrown in the creation of an environment's Malmo mission XML.
@@ -156,7 +159,8 @@ def _get_new_instance(self, port=None, instance_id=None):
         if InstanceManager.is_remote():
             launch_queue_logger_thread(instance, self.is_closed)
 
-        instance.launch()
+        with launch_instance_lock:
+            instance.launch()
         return instance
 
     def init(self):
diff --git a/requirements.txt b/requirements.txt
index 5d164d18e..9af9e11fc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,3 +13,4 @@ getch>=1.0; sys_platform != 'win32' and sys_platform != 'cygwin'
 coloredlogs>=10.0
 matplotlib==3.0.3
 dill>=0.3.1.1
+filelock