Fixed: Re-processing imported download causing task to fail

src/NzbDrone.Core/MediaFiles/DownloadedBooksImportService.cs

@@ -109,6 +109,8 @@ namespace NzbDrone.Core.MediaFiles
         }
 
         public bool ShouldDeleteFolder(IDirectoryInfo directoryInfo, Author author)
+        {
+            try
             {
                 var bookFiles = _diskScanService.GetBookFiles(directoryInfo.FullName);
                 var rarFiles = _diskProvider.GetFiles(directoryInfo.FullName, SearchOption.AllDirectories).Where(f => Path.GetExtension(f).Equals(".rar", StringComparison.OrdinalIgnoreCase));
@@ -135,6 +137,12 @@ namespace NzbDrone.Core.MediaFiles
 
                 return true;
             }
+            catch (DirectoryNotFoundException e)
+            {
+                _logger.Debug(e, "Folder {0} has already been removed", directoryInfo.FullName);
+                return false;
+            }
+        }
 
         private List<ImportResult> ProcessFolder(IDirectoryInfo directoryInfo, ImportMode importMode, DownloadClientItem downloadClientItem)
         {