diff --git a/lib/vagrant/machine.rb b/lib/vagrant/machine.rb
index de703842c..3806366d0 100644
--- a/lib/vagrant/machine.rb
+++ b/lib/vagrant/machine.rb
@@ -109,6 +109,7 @@ module Vagrant
       @provider_options = provider_options
       @ui              = Vagrant::UI::Prefixed.new(@env.ui, @name)
       @ui_mutex        = Mutex.new
+      @state_mutex     = Mutex.new
 
       # Read the ID, which is usually in local storage
       @id = nil
@@ -507,11 +508,17 @@ module Vagrant
       # master index.
       uuid = index_uuid
       if uuid
-        entry = @env.machine_index.get(uuid)
-        if entry
-          entry.state = result.short_description
-          @env.machine_index.set(entry)
-          @env.machine_index.release(entry)
+        # active_machines provides access to query this info on each machine
+        # from a different thread, ensure multiple machines do not access
+        # the locked entry simultaneously as this triggers a locked machine
+        # exception.
+        @state_mutex.synchronize do
+          entry = @env.machine_index.get(uuid)
+          if entry
+            entry.state = result.short_description
+            @env.machine_index.set(entry)
+            @env.machine_index.release(entry)
+          end
         end
       end
 
diff --git a/plugins/provisioners/ansible/provisioner/host.rb b/plugins/provisioners/ansible/provisioner/host.rb
index 83a614a10..5b35749d1 100644
--- a/plugins/provisioners/ansible/provisioner/host.rb
+++ b/plugins/provisioners/ansible/provisioner/host.rb
@@ -139,8 +139,15 @@ module VagrantPlugins
           inventory_file = Pathname.new(File.join(inventory_path, 'vagrant_ansible_inventory'))
           @@lock.synchronize do
             if !File.exists?(inventory_file) or inventory_content != File.read(inventory_file)
-              inventory_file.open('w') do |file|
-                file.write(inventory_content)
+              begin
+                # ansible dir inventory will ignore files starting with '.'
+                inventory_tmpfile = Tempfile.new('.vagrant_ansible_inventory', inventory_path)
+                inventory_tmpfile.write(inventory_content)
+                inventory_tmpfile.close
+                File.rename(inventory_tmpfile.path, inventory_file)
+              ensure
+                inventory_tmpfile.close
+                inventory_tmpfile.unlink
               end
             end
           end