diff --git a/lib/vagrant-parallels/action/box_register.rb b/lib/vagrant-parallels/action/box_register.rb
index 8ad4530a..2927b297 100644
--- a/lib/vagrant-parallels/action/box_register.rb
+++ b/lib/vagrant-parallels/action/box_register.rb
@@ -1,3 +1,4 @@
+require 'fileutils'
 require 'log4r'
 
 module VagrantPlugins
@@ -58,13 +59,35 @@ def box_id(env, box_path)
               config: tpl_config
           end
 
-          id
+          id.delete('{}')
+        end
+
+        def lease_box_lock(env)
+          lease_file = env[:machine].box.directory.join('box_lease_count')
+
+          # If the temporary file, verify it is not too old. If its older than
+          # 1 hour, delete it first because previous run may be failed.
+          if lease_file.file? && lease_file.mtime.to_i < Time.now.to_i - 60 * 60
+            lease_file.delete
+          end
+
+          # Increment a counter in the file. Create the file if it doesn't exist
+          FileUtils.touch(lease_file)
+          File.open(lease_file ,'r+') do |file|
+            num = file.gets.to_i
+            file.rewind
+            file.puts num.next
+            file.fsync
+            file.flush
+          end
         end
 
         def register_box(env)
-          box_id_file = env[:machine].box.directory.join('box_id')
+          # Increment the lock counter in the temporary lease file
+          lease_box_lock(env)
 
-          # Read the master ID if we have it in the file.
+          # Read the box ID if we have it in the file.
+          box_id_file = env[:machine].box.directory.join('box_id')
           env[:clone_id] = box_id_file.read.chomp if box_id_file.file?
 
           # If we have the ID and the VM exists already, then we
diff --git a/lib/vagrant-parallels/action/box_unregister.rb b/lib/vagrant-parallels/action/box_unregister.rb
index 448a9cf0..fb00e4ee 100644
--- a/lib/vagrant-parallels/action/box_unregister.rb
+++ b/lib/vagrant-parallels/action/box_unregister.rb
@@ -4,6 +4,8 @@ module VagrantPlugins
   module Parallels
     module Action
       class BoxUnregister
+        @@lock = Mutex.new
+
         def initialize(app, env)
           @app = app
           @logger = Log4r::Logger.new('vagrant_parallels::action::box_unregister')
@@ -15,7 +17,12 @@ def call(env)
             return @app.call(env)
           end
 
-          unregister_box(env)
+          @@lock.synchronize do
+            lock_key = Digest::MD5.hexdigest(env[:machine].box.name)
+            env[:machine].env.lock(lock_key, retry: true) do
+              unregister_box(env)
+            end
+          end
 
           # If we got interrupted, then the import could have been
           # interrupted and its not a big deal. Just return out.
@@ -31,7 +38,32 @@ def recover(env)
 
         private
 
+        def release_box_lock(lease_file)
+          return if !lease_file.file?
+
+          # Decrement the counter in the lease file
+          File.open(lease_file,'r+') do |file|
+            num = file.gets.to_i
+            file.rewind
+            file.puts(num - 1)
+            file.fsync
+            file.flush
+          end
+
+          # Delete the lease file if we are the last who need this box.
+          # Then the box image will be unregistered.
+          lease_file.delete if lease_file.read.chomp.to_i <= 1
+        end
+
         def unregister_box(env)
+          # Release the box lock
+          lease_file = env[:machine].box.directory.join('box_lease_count')
+          release_box_lock(lease_file)
+
+          # Do not unregister the box image if the temporary lease file exists
+          # Most likely it is cloning to another Vagrant env (in parallel run)
+          return if lease_file.file?
+
           if env[:clone_id] && env[:machine].provider.driver.vm_exists?(env[:clone_id])
             env[:ui].info I18n.t('vagrant_parallels.actions.vm.box.unregister')
             env[:machine].provider.driver.unregister(env[:clone_id])
diff --git a/lib/vagrant-parallels/driver/base.rb b/lib/vagrant-parallels/driver/base.rb
index ae3b9db2..2437a869 100644
--- a/lib/vagrant-parallels/driver/base.rb
+++ b/lib/vagrant-parallels/driver/base.rb
@@ -529,25 +529,7 @@ def regenerate_src_uuid
         # @param [String] pvm_file Path to the machine image (*.pvm)
         # @param [Array<String>] opts List of options for "prlctl register"
         def register(pvm_file, opts=[])
-          args = [@prlctl_path, 'register', pvm_file, *opts]
-
-          3.times do
-            result = raw(*args)
-            # Exit if everything is OK
-            return if result.exit_code == 0
-
-            # It may occur in the race condition with other Vagrant processes.
-            # It is OK, just exit.
-            return if result.stderr.include?('is already registered.')
-
-            # Sleep a bit though to give Parallels Desktop time to fix itself
-            sleep 2
-          end
-
-          # If we reach this point, it means that we consistently got the
-          # failure, do a standard execute now. This will raise an
-          # exception if it fails again.
-          execute(*args)
+          execute_prlctl('register', pvm_file, *opts)
         end
 
         # Switches the VM state to the specified snapshot
@@ -622,25 +604,7 @@ def suspend
         # Virtual machine will be removed from the VM list, but its image will
         # not be deleted from the disk. So, it can be registered again.
         def unregister(uuid)
-          args = [@prlctl_path, 'unregister', uuid]
-          3.times do
-            result = raw(*args)
-            # Exit if everything is OK
-            return if result.exit_code == 0
-
-            # It may occur in the race condition with other Vagrant processes.
-            # Both are OK, just exit.
-            return if result.stderr.include?('is not registered')
-            return if result.stderr.include?('is being cloned')
-
-            # Sleep a bit though to give Parallels Desktop time to fix itself
-            sleep 2
-          end
-
-          # If we reach this point, it means that we consistently got the
-          # failure, do a standard execute now. This will raise an
-          # exception if it fails again.
-          execute(*args)
+          execute_prlctl('unregister', uuid)
         end
 
         # Unshare folders.