diff --git a/NzbDrone.Common/DiskProvider.cs b/NzbDrone.Common/DiskProvider.cs
index 77920b144..f207af40b 100644
--- a/NzbDrone.Common/DiskProvider.cs
+++ b/NzbDrone.Common/DiskProvider.cs
@@ -232,5 +232,41 @@ namespace NzbDrone.Common
         {
             Directory.SetLastWriteTimeUtc(path, dateTime);
         }
+
+        public virtual bool IsFolderLocked(string path)
+        {
+            var files = GetFileInfos(path, "*.*", SearchOption.AllDirectories);
+
+            foreach(var fileInfo in files)
+            {
+                if (IsFileLocked(fileInfo))
+                    return true;
+            }
+
+            return false;
+        }
+
+        public virtual bool IsFileLocked(FileInfo file)
+        {
+            FileStream stream = null;
+
+            try
+            {
+                stream = file.Open(FileMode.Open, FileAccess.Read, FileShare.None);
+            }
+            catch (IOException)
+            {
+                return true;
+            }
+            finally
+            {
+                if (stream != null)
+                    stream.Close();
+            }
+
+            //file is not locked
+            return false;
+        }
+
     }
 }
\ No newline at end of file
diff --git a/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessDownloadFixture.cs b/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessDownloadFixture.cs
index b538a3576..de0ad4597 100644
--- a/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessDownloadFixture.cs
+++ b/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessDownloadFixture.cs
@@ -300,6 +300,7 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
             Mocker.GetMock<DiskProvider>().Setup(s => s.GetDirectorySize(droppedFolder.FullName)).Returns(Constants.IgnoreFileSize - 1.Megabytes());
             Mocker.GetMock<DiskProvider>().Setup(s => s.DeleteFolder(droppedFolder.FullName, true));
             Mocker.GetMock<DiskProvider>().Setup(s => s.FolderExists(fakeSeries.Path)).Returns(true);
+            Mocker.GetMock<DiskProvider>().Setup(s => s.IsFolderLocked(droppedFolder.FullName)).Returns(false);
             Mocker.GetMock<MetadataProvider>().Setup(s => s.CreateForEpisodeFiles(It.IsAny<List<EpisodeFile>>()));
 
             //Act
@@ -434,5 +435,21 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
             Mocker.GetMock<DiskProvider>().Verify(c => c.GetDirectorySize(It.IsAny<String>()), Times.Never());
             ExceptionVerification.ExpectedWarns(1);
         }
+
+        [Test]
+        public void should_skip_if_folder_is_in_use_by_another_process()
+        {
+            var downloadName = new DirectoryInfo(@"C:\Test\Drop\30.Rock.S01E01.Pilot");
+
+            WithValidSeries();
+
+            Mocker.GetMock<DiskProvider>()
+                    .Setup(s => s.IsFolderLocked(downloadName.FullName))
+                    .Returns(true);
+
+            Mocker.Resolve<PostDownloadProvider>().ProcessDownload(downloadName);
+
+            Mocker.GetMock<DiskProvider>().Verify(c => c.GetDirectorySize(It.IsAny<String>()), Times.Never());
+        }
     }
 }
\ No newline at end of file
diff --git a/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessVideoFileFixture.cs b/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessVideoFileFixture.cs
index d4413aa36..2f5535f93 100644
--- a/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessVideoFileFixture.cs
+++ b/NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessVideoFileFixture.cs
@@ -227,14 +227,6 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
 
             WithValidSeries();
 
-            Mocker.GetMock<DiskProvider>()
-                    .Setup(s => s.GetDirectorySize(downloadName))
-                    .Returns(10);
-
-            Mocker.GetMock<DiskProvider>()
-                    .Setup(s => s.FreeDiskSpace(It.IsAny<DirectoryInfo>()))
-                    .Returns(10);
-
             Mocker.GetMock<DiskProvider>()
                                 .Setup(s => s.FolderExists(fakeSeries.Path))
                                 .Returns(false);
@@ -246,5 +238,24 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
             //Assert
             ExceptionVerification.ExpectedWarns(1);
         }
+
+        [Test]
+        public void should_skip_if_file_is_in_use_by_another_process()
+        {
+            var downloadName = @"C:\Test\Drop\30.Rock.S01E01.Pilot.mkv";
+
+            WithValidSeries();
+
+            Mocker.GetMock<DiskProvider>()
+                                .Setup(s => s.IsFileLocked(It.Is<FileInfo>(f => f.FullName == downloadName)))
+                                .Returns(true);
+
+            //Act
+            Mocker.Resolve<PostDownloadProvider>().ProcessVideoFile(downloadName);
+
+
+            //Assert
+            Mocker.GetMock<DiskScanProvider>().Verify(c => c.ImportFile(fakeSeries, downloadName), Times.Never());
+        }
     }
 }
\ No newline at end of file
diff --git a/NzbDrone.Core/Providers/PostDownloadProvider.cs b/NzbDrone.Core/Providers/PostDownloadProvider.cs
index e0e4ef874..22208e732 100644
--- a/NzbDrone.Core/Providers/PostDownloadProvider.cs
+++ b/NzbDrone.Core/Providers/PostDownloadProvider.cs
@@ -71,6 +71,12 @@ namespace NzbDrone.Core.Providers
                 return;
             }
 
+            if (_diskProvider.IsFolderLocked(subfolderInfo.FullName))
+            {
+                Logger.Trace("[{0}] is currently locked by another process, skipping", subfolderInfo.Name);
+                return;
+            }
+
             string seriesName = Parser.ParseSeriesName(RemoveStatusFromFolderName(subfolderInfo.Name));
             var series = _seriesProvider.FindSeries(seriesName);
 
@@ -135,6 +141,12 @@ namespace NzbDrone.Core.Providers
                 return;
             }
 
+            if (_diskProvider.IsFileLocked(new FileInfo(videoFile)))
+            {
+                Logger.Trace("[{0}] is currently locked by another process, skipping", videoFile);
+                return;
+            }
+
             var seriesName = Parser.ParseSeriesName(Path.GetFileNameWithoutExtension(videoFile));
             var series = _seriesProvider.FindSeries(seriesName);