diff --git a/src/NzbDrone.Common.Test/EnsureTest/PathExtensionFixture.cs b/src/NzbDrone.Common.Test/EnsureTest/PathExtensionFixture.cs
index 53c1b42f4..42a65f9b1 100644
--- a/src/NzbDrone.Common.Test/EnsureTest/PathExtensionFixture.cs
+++ b/src/NzbDrone.Common.Test/EnsureTest/PathExtensionFixture.cs
@@ -1,4 +1,5 @@
 using NUnit.Framework;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.EnsureThat;
 using NzbDrone.Test.Common;
 
@@ -12,14 +13,14 @@ namespace NzbDrone.Common.Test.EnsureTest
         public void EnsureWindowsPath(string path)
         {
             WindowsOnly();
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
         }
 
         [TestCase(@"/var/user/file with, comma.mkv")]
         public void EnsureLinuxPath(string path)
         {
             PosixOnly();
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
         }
     }
 }
diff --git a/src/NzbDrone.Common.Test/PathExtensionFixture.cs b/src/NzbDrone.Common.Test/PathExtensionFixture.cs
index a01c6dc1a..a33a53c01 100644
--- a/src/NzbDrone.Common.Test/PathExtensionFixture.cs
+++ b/src/NzbDrone.Common.Test/PathExtensionFixture.cs
@@ -35,6 +35,7 @@ namespace NzbDrone.Common.Test
         [TestCase(@"\\Testserver\Test\file.ext", @"\\Testserver\Test\file.ext")]
         [TestCase(@"\\Testserver\Test\file.ext\\", @"\\Testserver\Test\file.ext")]
         [TestCase(@"\\Testserver\Test\file.ext   \\", @"\\Testserver\Test\file.ext")]
+        [TestCase(@"//CAPITAL//lower// ", @"\\CAPITAL\lower")]
         public void Clean_Path_Windows(string dirty, string clean)
         {
             WindowsOnly();
diff --git a/src/NzbDrone.Common/Disk/DiskProviderBase.cs b/src/NzbDrone.Common/Disk/DiskProviderBase.cs
index 29de0c1a6..5e9228236 100644
--- a/src/NzbDrone.Common/Disk/DiskProviderBase.cs
+++ b/src/NzbDrone.Common/Disk/DiskProviderBase.cs
@@ -65,7 +65,7 @@ namespace NzbDrone.Common.Disk
 
         private void CheckFolderExists(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             if (!FolderExists(path))
             {
@@ -75,7 +75,7 @@ namespace NzbDrone.Common.Disk
 
         private void CheckFileExists(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             if (!FileExists(path))
             {
@@ -93,19 +93,19 @@ namespace NzbDrone.Common.Disk
 
         public bool FolderExists(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
             return Directory.Exists(path);
         }
 
         public bool FileExists(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
             return FileExists(path, PathStringComparison);
         }
 
         public bool FileExists(string path, StringComparison stringComparison)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             switch (stringComparison)
             {
@@ -125,7 +125,7 @@ namespace NzbDrone.Common.Disk
 
         public bool FolderWritable(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             try
             {
@@ -144,35 +144,35 @@ namespace NzbDrone.Common.Disk
 
         public bool FolderEmpty(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             return Directory.EnumerateFileSystemEntries(path).Empty();
         }
 
         public string[] GetDirectories(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             return Directory.GetDirectories(path);
         }
 
         public string[] GetFiles(string path, SearchOption searchOption)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             return Directory.GetFiles(path, "*.*", searchOption);
         }
 
         public long GetFolderSize(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             return GetFiles(path, SearchOption.AllDirectories).Sum(e => new FileInfo(e).Length);
         }
 
         public long GetFileSize(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             if (!FileExists(path))
             {
@@ -185,13 +185,13 @@ namespace NzbDrone.Common.Disk
 
         public void CreateFolder(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
             Directory.CreateDirectory(path);
         }
 
         public void DeleteFile(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
             Logger.Trace("Deleting file: {0}", path);
 
             RemoveReadOnly(path);
@@ -201,8 +201,8 @@ namespace NzbDrone.Common.Disk
 
         public void CloneFile(string source, string destination, bool overwrite = false)
         {
-            Ensure.That(source, () => source).IsValidPath();
-            Ensure.That(destination, () => destination).IsValidPath();
+            Ensure.That(source, () => source).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(destination, () => destination).IsValidPath(PathValidationType.CurrentOs);
 
             if (source.PathEquals(destination))
             {
@@ -219,8 +219,8 @@ namespace NzbDrone.Common.Disk
 
         public void CopyFile(string source, string destination, bool overwrite = false)
         {
-            Ensure.That(source, () => source).IsValidPath();
-            Ensure.That(destination, () => destination).IsValidPath();
+            Ensure.That(source, () => source).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(destination, () => destination).IsValidPath(PathValidationType.CurrentOs);
 
             if (source.PathEquals(destination))
             {
@@ -237,8 +237,8 @@ namespace NzbDrone.Common.Disk
 
         public void MoveFile(string source, string destination, bool overwrite = false)
         {
-            Ensure.That(source, () => source).IsValidPath();
-            Ensure.That(destination, () => destination).IsValidPath();
+            Ensure.That(source, () => source).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(destination, () => destination).IsValidPath(PathValidationType.CurrentOs);
 
             if (source.PathEquals(destination))
             {
@@ -256,8 +256,8 @@ namespace NzbDrone.Common.Disk
 
         public void MoveFolder(string source, string destination, bool overwrite = false)
         {
-            Ensure.That(source, () => source).IsValidPath();
-            Ensure.That(destination, () => destination).IsValidPath();
+            Ensure.That(source, () => source).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(destination, () => destination).IsValidPath(PathValidationType.CurrentOs);
 
             Directory.Move(source, destination);
         }
@@ -281,7 +281,7 @@ namespace NzbDrone.Common.Disk
 
         public void DeleteFolder(string path, bool recursive)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var files = Directory.GetFiles(path, "*.*", recursive ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly);
             Array.ForEach(files, RemoveReadOnly);
@@ -291,14 +291,14 @@ namespace NzbDrone.Common.Disk
 
         public string ReadAllText(string filePath)
         {
-            Ensure.That(filePath, () => filePath).IsValidPath();
+            Ensure.That(filePath, () => filePath).IsValidPath(PathValidationType.CurrentOs);
 
             return File.ReadAllText(filePath);
         }
 
         public void WriteAllText(string filename, string contents)
         {
-            Ensure.That(filename, () => filename).IsValidPath();
+            Ensure.That(filename, () => filename).IsValidPath(PathValidationType.CurrentOs);
             RemoveReadOnly(filename);
 
             // File.WriteAllText is broken on net core when writing to some CIFS mounts
@@ -314,7 +314,7 @@ namespace NzbDrone.Common.Disk
 
         public void FolderSetLastWriteTime(string path, DateTime dateTime)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             if (dateTime.Before(DateTimeExtensions.Epoch))
             {
@@ -326,7 +326,7 @@ namespace NzbDrone.Common.Disk
 
         public void FileSetLastWriteTime(string path, DateTime dateTime)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             if (dateTime.Before(DateTimeExtensions.Epoch))
             {
@@ -353,14 +353,14 @@ namespace NzbDrone.Common.Disk
 
         public virtual string GetPathRoot(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             return Path.GetPathRoot(path);
         }
 
         public string GetParentFolder(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var parent = Directory.GetParent(path.TrimEnd(Path.DirectorySeparatorChar));
 
@@ -407,7 +407,7 @@ namespace NzbDrone.Common.Disk
 
         public void EmptyFolder(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             foreach (var file in GetFiles(path, SearchOption.TopDirectoryOnly))
             {
@@ -496,7 +496,7 @@ namespace NzbDrone.Common.Disk
 
         public List<DirectoryInfo> GetDirectoryInfos(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var di = new DirectoryInfo(path);
 
@@ -505,14 +505,14 @@ namespace NzbDrone.Common.Disk
 
         public FileInfo GetFileInfo(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             return new FileInfo(path);
         }
 
         public List<FileInfo> GetFileInfos(string path, SearchOption searchOption = SearchOption.TopDirectoryOnly)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var di = new DirectoryInfo(path);
 
diff --git a/src/NzbDrone.Common/Disk/DiskTransferService.cs b/src/NzbDrone.Common/Disk/DiskTransferService.cs
index 44d28a9df..83d815348 100644
--- a/src/NzbDrone.Common/Disk/DiskTransferService.cs
+++ b/src/NzbDrone.Common/Disk/DiskTransferService.cs
@@ -43,8 +43,8 @@ namespace NzbDrone.Common.Disk
 
         public TransferMode TransferFolder(string sourcePath, string targetPath, TransferMode mode)
         {
-            Ensure.That(sourcePath, () => sourcePath).IsValidPath();
-            Ensure.That(targetPath, () => targetPath).IsValidPath();
+            Ensure.That(sourcePath, () => sourcePath).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(targetPath, () => targetPath).IsValidPath(PathValidationType.CurrentOs);
 
             sourcePath = ResolveRealParentPath(sourcePath);
             targetPath = ResolveRealParentPath(targetPath);
@@ -140,8 +140,8 @@ namespace NzbDrone.Common.Disk
         {
             var filesCopied = 0;
 
-            Ensure.That(sourcePath, () => sourcePath).IsValidPath();
-            Ensure.That(targetPath, () => targetPath).IsValidPath();
+            Ensure.That(sourcePath, () => sourcePath).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(targetPath, () => targetPath).IsValidPath(PathValidationType.CurrentOs);
 
             sourcePath = ResolveRealParentPath(sourcePath);
             targetPath = ResolveRealParentPath(targetPath);
@@ -255,8 +255,8 @@ namespace NzbDrone.Common.Disk
 
         public TransferMode TransferFile(string sourcePath, string targetPath, TransferMode mode, bool overwrite = false)
         {
-            Ensure.That(sourcePath, () => sourcePath).IsValidPath();
-            Ensure.That(targetPath, () => targetPath).IsValidPath();
+            Ensure.That(sourcePath, () => sourcePath).IsValidPath(PathValidationType.CurrentOs);
+            Ensure.That(targetPath, () => targetPath).IsValidPath(PathValidationType.CurrentOs);
 
             sourcePath = ResolveRealParentPath(sourcePath);
             targetPath = ResolveRealParentPath(targetPath);
diff --git a/src/NzbDrone.Common/Disk/FileSystemLookupService.cs b/src/NzbDrone.Common/Disk/FileSystemLookupService.cs
index 63529697e..8b9d1bae0 100644
--- a/src/NzbDrone.Common/Disk/FileSystemLookupService.cs
+++ b/src/NzbDrone.Common/Disk/FileSystemLookupService.cs
@@ -71,7 +71,7 @@ namespace NzbDrone.Common.Disk
 
             if (
                 allowFoldersWithoutTrailingSlashes &&
-                query.IsPathValid() &&
+                query.IsPathValid(PathValidationType.CurrentOs) &&
                 _diskProvider.FolderExists(query))
             {
                 return GetResult(query, includeFiles);
diff --git a/src/NzbDrone.Common/Disk/OsPath.cs b/src/NzbDrone.Common/Disk/OsPath.cs
index c4327ddeb..84942a186 100644
--- a/src/NzbDrone.Common/Disk/OsPath.cs
+++ b/src/NzbDrone.Common/Disk/OsPath.cs
@@ -162,7 +162,7 @@ namespace NzbDrone.Common.Disk
             }
         }
 
-        public bool IsValid => _path.IsPathValid();
+        public bool IsValid => _path.IsPathValid(PathValidationType.CurrentOs);
 
         private int GetFileNameIndex()
         {
diff --git a/src/NzbDrone.Common/Disk/PathValidationType.cs b/src/NzbDrone.Common/Disk/PathValidationType.cs
new file mode 100644
index 000000000..395e3f0d8
--- /dev/null
+++ b/src/NzbDrone.Common/Disk/PathValidationType.cs
@@ -0,0 +1,8 @@
+namespace NzbDrone.Common.Disk
+{
+    public enum PathValidationType
+    {
+        CurrentOs,
+        AnyOs
+    }
+}
diff --git a/src/NzbDrone.Common/EnsureThat/EnsureStringExtensions.cs b/src/NzbDrone.Common/EnsureThat/EnsureStringExtensions.cs
index 1c10c9f28..ba02ee7f6 100644
--- a/src/NzbDrone.Common/EnsureThat/EnsureStringExtensions.cs
+++ b/src/NzbDrone.Common/EnsureThat/EnsureStringExtensions.cs
@@ -1,5 +1,6 @@
 using System.Diagnostics;
 using System.Text.RegularExpressions;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.EnsureThat.Resources;
 using NzbDrone.Common.EnvironmentInfo;
 using NzbDrone.Common.Extensions;
@@ -111,14 +112,14 @@ namespace NzbDrone.Common.EnsureThat
         }
 
         [DebuggerStepThrough]
-        public static Param<string> IsValidPath(this Param<string> param)
+        public static Param<string> IsValidPath(this Param<string> param, PathValidationType validationType)
         {
             if (string.IsNullOrWhiteSpace(param.Value))
             {
                 throw ExceptionFactory.CreateForParamValidation(param.Name, ExceptionMessages.EnsureExtensions_IsNotNullOrWhiteSpace);
             }
 
-            if (param.Value.IsPathValid())
+            if (param.Value.IsPathValid(validationType))
             {
                 return param;
             }
diff --git a/src/NzbDrone.Common/Extensions/PathExtensions.cs b/src/NzbDrone.Common/Extensions/PathExtensions.cs
index cf82e601c..f2d82f10e 100644
--- a/src/NzbDrone.Common/Extensions/PathExtensions.cs
+++ b/src/NzbDrone.Common/Extensions/PathExtensions.cs
@@ -29,12 +29,12 @@ namespace NzbDrone.Common.Extensions
         public static string CleanFilePath(this string path)
         {
             Ensure.That(path, () => path).IsNotNullOrWhiteSpace();
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.AnyOs);
 
             var info = new FileInfo(path.Trim());
 
             // UNC
-            if (OsInfo.IsWindows && info.FullName.StartsWith(@"\\"))
+            if (!info.FullName.Contains('/') && info.FullName.StartsWith(@"\\"))
             {
                 return info.FullName.TrimEnd('/', '\\', ' ');
             }
@@ -136,24 +136,24 @@ namespace NzbDrone.Common.Extensions
 
         private static readonly Regex WindowsPathWithDriveRegex = new Regex(@"^[a-zA-Z]:\\", RegexOptions.Compiled);
 
-        public static bool IsPathValid(this string path)
+        public static bool IsPathValid(this string path, PathValidationType validationType)
         {
             if (path.ContainsInvalidPathChars() || string.IsNullOrWhiteSpace(path))
             {
                 return false;
             }
 
-            if (OsInfo.IsNotWindows)
+            if (validationType == PathValidationType.AnyOs)
             {
-                return path.StartsWith(Path.DirectorySeparatorChar.ToString());
+                return IsPathValidForWindows(path) || IsPathValidForNonWindows(path);
             }
 
-            if (path.StartsWith("\\") || WindowsPathWithDriveRegex.IsMatch(path))
+            if (OsInfo.IsNotWindows)
             {
-                return true;
+                return IsPathValidForNonWindows(path);
             }
 
-            return false;
+            return IsPathValidForWindows(path);
         }
 
         public static bool ContainsInvalidPathChars(this string text)
@@ -337,5 +337,15 @@ namespace NzbDrone.Common.Extensions
         {
             return Path.Combine(appFolderInfo.StartUpFolder, NLOG_CONFIG_FILE);
         }
+
+        private static bool IsPathValidForWindows(string path)
+        {
+            return path.StartsWith("\\") || WindowsPathWithDriveRegex.IsMatch(path);
+        }
+
+        private static bool IsPathValidForNonWindows(string path)
+        {
+            return path.StartsWith("/");
+        }
     }
 }
diff --git a/src/NzbDrone.Common/PathEqualityComparer.cs b/src/NzbDrone.Common/PathEqualityComparer.cs
index d443a3bf0..958b700db 100644
--- a/src/NzbDrone.Common/PathEqualityComparer.cs
+++ b/src/NzbDrone.Common/PathEqualityComparer.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.EnvironmentInfo;
 using NzbDrone.Common.Extensions;
 
diff --git a/src/NzbDrone.Core/Validation/FolderValidator.cs b/src/NzbDrone.Core/Validation/FolderValidator.cs
index 6f88c9009..405fe14bd 100644
--- a/src/NzbDrone.Core/Validation/FolderValidator.cs
+++ b/src/NzbDrone.Core/Validation/FolderValidator.cs
@@ -1,4 +1,5 @@
-using FluentValidation.Validators;
+using FluentValidation.Validators;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Core.Validation
@@ -14,7 +15,7 @@ namespace NzbDrone.Core.Validation
                 return false;
             }
 
-            return context.PropertyValue.ToString().IsPathValid();
+            return context.PropertyValue.ToString().IsPathValid(PathValidationType.CurrentOs);
         }
     }
 }
diff --git a/src/NzbDrone.Core/Validation/Paths/PathValidator.cs b/src/NzbDrone.Core/Validation/Paths/PathValidator.cs
index fe0b496ed..831d0e2a7 100644
--- a/src/NzbDrone.Core/Validation/Paths/PathValidator.cs
+++ b/src/NzbDrone.Core/Validation/Paths/PathValidator.cs
@@ -1,5 +1,6 @@
-using FluentValidation;
+using FluentValidation;
 using FluentValidation.Validators;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Core.Validation.Paths
@@ -23,7 +24,7 @@ namespace NzbDrone.Core.Validation.Paths
                 return false;
             }
 
-            return context.PropertyValue.ToString().IsPathValid();
+            return context.PropertyValue.ToString().IsPathValid(PathValidationType.CurrentOs);
         }
     }
 }
diff --git a/src/NzbDrone.Mono/Disk/DiskProvider.cs b/src/NzbDrone.Mono/Disk/DiskProvider.cs
index e8d25b3e8..720bf211c 100644
--- a/src/NzbDrone.Mono/Disk/DiskProvider.cs
+++ b/src/NzbDrone.Mono/Disk/DiskProvider.cs
@@ -40,7 +40,7 @@ namespace NzbDrone.Mono.Disk
 
         public override long? GetAvailableSpace(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var mount = GetMount(path);
 
@@ -217,7 +217,7 @@ namespace NzbDrone.Mono.Disk
 
         public override long? GetTotalSize(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var mount = GetMount(path);
 
diff --git a/src/NzbDrone.Windows/Disk/DiskProvider.cs b/src/NzbDrone.Windows/Disk/DiskProvider.cs
index 3200e669b..f65dae3d0 100644
--- a/src/NzbDrone.Windows/Disk/DiskProvider.cs
+++ b/src/NzbDrone.Windows/Disk/DiskProvider.cs
@@ -35,7 +35,7 @@ namespace NzbDrone.Windows.Disk
 
         public override string GetPathRoot(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var reparsePoint = GetReparsePoint(path);
 
@@ -44,7 +44,7 @@ namespace NzbDrone.Windows.Disk
 
         public override long? GetAvailableSpace(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var root = GetPathRoot(path);
 
@@ -58,7 +58,7 @@ namespace NzbDrone.Windows.Disk
 
         public override void InheritFolderPermissions(string filename)
         {
-            Ensure.That(filename, () => filename).IsValidPath();
+            Ensure.That(filename, () => filename).IsValidPath(PathValidationType.CurrentOs);
 
             var fileInfo = new FileInfo(filename);
             var fs = fileInfo.GetAccessControl(AccessControlSections.Access);
@@ -121,7 +121,7 @@ namespace NzbDrone.Windows.Disk
 
         public override long? GetTotalSize(string path)
         {
-            Ensure.That(path, () => path).IsValidPath();
+            Ensure.That(path, () => path).IsValidPath(PathValidationType.CurrentOs);
 
             var root = GetPathRoot(path);
 
@@ -135,7 +135,7 @@ namespace NzbDrone.Windows.Disk
 
         private static long DriveFreeSpaceEx(string folderName)
         {
-            Ensure.That(folderName, () => folderName).IsValidPath();
+            Ensure.That(folderName, () => folderName).IsValidPath(PathValidationType.CurrentOs);
 
             if (!folderName.EndsWith("\\"))
             {
@@ -156,7 +156,7 @@ namespace NzbDrone.Windows.Disk
 
         private static long DriveTotalSizeEx(string folderName)
         {
-            Ensure.That(folderName, () => folderName).IsValidPath();
+            Ensure.That(folderName, () => folderName).IsValidPath(PathValidationType.CurrentOs);
 
             if (!folderName.EndsWith("\\"))
             {