Fixed removing partials before trying to copy files.

src/NzbDrone.Common.Test/DiskTests/DiskTransferServiceFixture.cs

@@ -378,7 +378,7 @@ namespace NzbDrone.Common.Test.DiskTests
         }
 
         [Test]
-        public void mode_transactional_should_delete_old_backup()
+        public void mode_transactional_should_delete_old_backup_on_move()
         {
             Subject.VerificationMode = DiskTransferVerificationMode.Transactional;
 
@@ -393,7 +393,7 @@ namespace NzbDrone.Common.Test.DiskTests
         }
 
         [Test]
-        public void mode_transactional_should_delete_old_partial()
+        public void mode_transactional_should_delete_old_partial_on_move()
         {
             Subject.VerificationMode = DiskTransferVerificationMode.Transactional;
 
@@ -407,6 +407,19 @@ namespace NzbDrone.Common.Test.DiskTests
                 .Verify(v => v.DeleteFile(_tempTargetPath), Times.Once());
         }
 
+        [Test]
+        public void mode_transactional_should_delete_old_partial_on_copy()
+        {
+            Subject.VerificationMode = DiskTransferVerificationMode.Transactional;
+
+            WithExistingFile(_tempTargetPath);
+
+            Subject.TransferFile(_sourcePath, _targetPath, TransferMode.Copy);
+
+            Mocker.GetMock<IDiskProvider>()
+                .Verify(v => v.DeleteFile(_tempTargetPath), Times.Once());
+        }
+
         [Test]
         public void mode_transactional_should_hardlink_before_move()
         {

src/NzbDrone.Common/Disk/DiskTransferService.cs

@@ -316,6 +316,12 @@ namespace NzbDrone.Common.Disk
 
             var tempTargetPath = targetPath + ".partial~";
 
+            if (_diskProvider.FileExists(tempTargetPath))
+            {
+                _logger.Trace("Removing old partial.");
+                _diskProvider.DeleteFile(tempTargetPath);
+            }
+
             try
             {
                 for (var i = 0; i <= RetryCount; i++)