GetActualCasing can partially fix the path for non-existing paths.

NzbDrone.Common.Test/PathExtensionFixture.cs

@@ -102,30 +102,31 @@ namespace NzbDrone.Common.Test
         }
 
         [Test]
-        public void get_actual_casing_for_none_existing_file_should_throw()
+        public void get_actual_casing_for_none_existing_file_return_partially_fixed_result()
         {
             WindowsOnly();
-            Assert.Throws<DirectoryNotFoundException>(() => "C:\\InValidFolder\\invalidfile.exe".GetActualCasing());
+           "C:\\WINDOWS\\invalidfile.exe".GetActualCasing().Should().Be("C:\\Windows\\invalidfile.exe");
         }
 
+
         [Test]
-        public void get_actual_casing_should_return_actual_casing_for_local_file_in_windows()
+        public void get_actual_casing_for_none_existing_folder_return_partially_fixed_result()
         {
             WindowsOnly();
-            var path = Process.GetCurrentProcess().MainModule.FileName;
-            path.ToUpper().GetActualCasing().Should().Be(path);
-            path.ToLower().GetActualCasing().Should().Be(path);
+            "C:\\WINDOWS\\SYSTEM32\\FAKEFOLDER\\invalidfile.exe".GetActualCasing().Should().Be("C:\\Windows\\System32\\FAKEFOLDER\\invalidfile.exe");
         }
 
         [Test]
-        public void get_actual_casing_should_return_origibal_value_in_linux()
+        public void get_actual_casing_should_return_actual_casing_for_local_file_in_windows()
         {
-            LinuxOnly();
+            WindowsOnly();
             var path = Process.GetCurrentProcess().MainModule.FileName;
-            path.GetActualCasing().Should().Be(path);
-            path.GetActualCasing().Should().Be(path);
+            path.ToUpper().GetActualCasing().Should().Be(path);
+            path.ToLower().GetActualCasing().Should().Be(path);
         }
 
+
+
         [Test]
         public void get_actual_casing_should_return_actual_casing_for_local_dir_in_windows()
         {

NzbDrone.Common/PathExtensions.cs

@@ -63,23 +63,27 @@ namespace NzbDrone.Common
 
         public static string GetActualCasing(this string path)
         {
-            var attributes = File.GetAttributes(path);
-
             if (OsInfo.IsLinux || path.StartsWith("\\"))
             {
                 return path;
             }
 
-            if ((attributes & FileAttributes.Directory) == FileAttributes.Directory)
+            if (Directory.Exists(path) && (File.GetAttributes(path) & FileAttributes.Directory) == FileAttributes.Directory)
             {
                 return GetProperCapitalization(new DirectoryInfo(path));
             }
 
             var fileInfo = new FileInfo(path);
+            var dirInfo = fileInfo.Directory;
+
+            var fileName = fileInfo.Name;
 
+            if (dirInfo != null && fileInfo.Exists)
+            {
+                fileName = dirInfo.GetFiles(fileInfo.Name)[0].Name;
+            }
 
-            DirectoryInfo dirInfo = fileInfo.Directory;
-            return Path.Combine(GetProperCapitalization(dirInfo), dirInfo.GetFiles(fileInfo.Name)[0].Name);
+            return Path.Combine(GetProperCapitalization(dirInfo), fileName);
         }
 
         public static string GetAppDataPath(this IAppFolderInfo appFolderInfo)