diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4e3add4d662..c28c3ee1b9c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -113,6 +113,12 @@
 
 [#49878]: https://github.com/dart-lang/sdk/issues/49878
 
+- When a `dart:io` operation fails because a file is not found, throw
+  `PathNotFoundException`, a `FileSystemException` subclass, to make it
+  easier to handle "file not found" errors.
+
+[#12461]: https://github.com/dart-lang/sdk/issues/12461
+
 #### `dart:isolate`
 
 - Add `Isolate.run` to run a function in a new isolate.
diff --git a/runtime/bin/directory.cc b/runtime/bin/directory.cc
index 9920d0f08b4..4143039b953 100644
--- a/runtime/bin/directory.cc
+++ b/runtime/bin/directory.cc
@@ -571,13 +571,13 @@ bool SyncDirectoryListing::HandleFile(const char* file_name) {
 bool SyncDirectoryListing::HandleError() {
   Dart_Handle dart_os_error = DartUtils::NewDartOSError();
   Dart_Handle args[3];
-  args[0] = DartUtils::NewString("Directory listing failed");
-  args[1] = DartUtils::NewString(error() ? "Invalid path" : CurrentPath());
-  args[2] = dart_os_error;
+  args[0] = dart_os_error;
+  args[1] = DartUtils::NewString("Directory listing failed");
+  args[2] = DartUtils::NewString(error() ? "Invalid path" : CurrentPath());
 
   dart_error_ = Dart_New(
       DartUtils::GetDartType(DartUtils::kIOLibURL, "FileSystemException"),
-      Dart_Null(), 3, args);
+      DartUtils::NewString("_fromOSError"), 3, args);
   return false;
 }
 
diff --git a/runtime/observatory/tests/service/dev_fs_test.dart b/runtime/observatory/tests/service/dev_fs_test.dart
index 159c499a6f2..5cec872fc87 100644
--- a/runtime/observatory/tests/service/dev_fs_test.dart
+++ b/runtime/observatory/tests/service/dev_fs_test.dart
@@ -74,7 +74,7 @@ var tests = <VMTest>[
     } on ServerRpcException catch (e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kFileDoesNotExist));
-      expect(e.message, startsWith("_readDevFSFile: FileSystemException: "));
+      expect(e.message, startsWith("_readDevFSFile: PathNotFoundException: "));
     }
     expect(caughtException, isTrue);
 
diff --git a/runtime/observatory_2/tests/service_2/dev_fs_test.dart b/runtime/observatory_2/tests/service_2/dev_fs_test.dart
index 1cab8e5fb32..50eb5591b42 100644
--- a/runtime/observatory_2/tests/service_2/dev_fs_test.dart
+++ b/runtime/observatory_2/tests/service_2/dev_fs_test.dart
@@ -74,7 +74,7 @@ var tests = <VMTest>[
     } on ServerRpcException catch (e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kFileDoesNotExist));
-      expect(e.message, startsWith("_readDevFSFile: FileSystemException: "));
+      expect(e.message, startsWith("_readDevFSFile: PathNotFoundException: "));
     }
     expect(caughtException, isTrue);
 
diff --git a/sdk/lib/_internal/vm/bin/file_patch.dart b/sdk/lib/_internal/vm/bin/file_patch.dart
index 8851db10269..94f529dc864 100644
--- a/sdk/lib/_internal/vm/bin/file_patch.dart
+++ b/sdk/lib/_internal/vm/bin/file_patch.dart
@@ -172,8 +172,8 @@ abstract class _FileSystemWatcher {
         _id = _initWatcher();
         _newWatcher();
       } on dynamic catch (e) {
-        _broadcastController.addError(new FileSystemException(
-            "Failed to initialize file system entity watcher", null, e));
+        _broadcastController.addError(FileSystemException._fromOSError(
+            e, "Failed to initialize file system entity watcher", null));
         _broadcastController.close();
         return;
       }
@@ -183,8 +183,8 @@ abstract class _FileSystemWatcher {
       pathId =
           _watchPath(_id!, _Namespace._namespace, _path, _events, _recursive);
     } on dynamic catch (e) {
-      _broadcastController
-          .addError(new FileSystemException("Failed to watch path", _path, e));
+      _broadcastController.addError(
+          FileSystemException._fromOSError(e, "Failed to watch path", _path));
       _broadcastController.close();
       return;
     }
diff --git a/sdk/lib/io/common.dart b/sdk/lib/io/common.dart
index 3684b1fdb8c..00ca7ad6d67 100644
--- a/sdk/lib/io/common.dart
+++ b/sdk/lib/io/common.dart
@@ -15,6 +15,21 @@ const int _errorResponseErrorType = 0;
 const int _osErrorResponseErrorCode = 1;
 const int _osErrorResponseMessage = 2;
 
+// POSIX error codes.
+// See https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+const _eNoEnt = 2;
+
+// Windows error codes.
+// See https://learn.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499-
+const _errorFileNotFound = 2;
+const _errorPathNotFound = 3;
+const _errorInvalidDrive = 15;
+const _errorNoMoreFiles = 18;
+const _errorBadNetpath = 53;
+const _errorBadNetName = 67;
+const _errorBadPathName = 161;
+const _errorFilenameExedRange = 206;
+
 /// If the [response] is an error, throws an [Exception] or an [Error].
 void _checkForErrorResponse(Object? response, String message, String path) {
   if (response is List<Object?> && response[0] != _successResponse) {
@@ -24,7 +39,7 @@ void _checkForErrorResponse(Object? response, String message, String path) {
       case _osErrorResponse:
         var err = OSError(response[_osErrorResponseMessage] as String,
             response[_osErrorResponseErrorCode] as int);
-        throw FileSystemException(message, path, err);
+        throw FileSystemException._fromOSError(err, message, path);
       case _fileClosedResponse:
         throw FileSystemException("File closed", path);
       default:
@@ -64,12 +79,18 @@ class OSError implements Exception {
     StringBuffer sb = new StringBuffer();
     sb.write("OS Error");
     if (message.isNotEmpty) {
-      sb..write(": ")..write(message);
+      sb
+        ..write(": ")
+        ..write(message);
       if (errorCode != noErrorCode) {
-        sb..write(", errno = ")..write(errorCode.toString());
+        sb
+          ..write(", errno = ")
+          ..write(errorCode.toString());
       }
     } else if (errorCode != noErrorCode) {
-      sb..write(": errno = ")..write(errorCode.toString());
+      sb
+        ..write(": errno = ")
+        ..write(errorCode.toString());
     }
     return sb.toString();
   }
@@ -85,8 +106,7 @@ class _BufferAndStart {
 // Ensure that the input List can be serialized through a native port.
 _BufferAndStart _ensureFastAndSerializableByteData(
     List<int> buffer, int start, int end) {
-  if ((buffer is Uint8List) &&
-      (buffer.buffer.lengthInBytes == buffer.length)) {
+  if ((buffer is Uint8List) && (buffer.buffer.lengthInBytes == buffer.length)) {
     // Send typed data directly, unless it is a partial view, in which case we
     // would rather copy than drag in the potentially much large backing store.
     // See issue 50206.
diff --git a/sdk/lib/io/directory_impl.dart b/sdk/lib/io/directory_impl.dart
index ae8abf97123..c8ed9dfb14f 100644
--- a/sdk/lib/io/directory_impl.dart
+++ b/sdk/lib/io/directory_impl.dart
@@ -39,8 +39,8 @@ class _Directory extends FileSystemEntity implements Directory {
   static Directory get current {
     var result = _current(_Namespace._namespace);
     if (result is OSError) {
-      throw new FileSystemException(
-          "Getting current working directory failed", "", result);
+      throw FileSystemException._fromOSError(
+          result, "Getting current working directory failed", "");
     }
     return new _Directory(result);
   }
@@ -69,8 +69,8 @@ class _Directory extends FileSystemEntity implements Directory {
     var result = _setCurrent(_Namespace._namespace, _rawPath);
     if (result is ArgumentError) throw result;
     if (result is OSError) {
-      throw new FileSystemException(
-          "Setting current working directory failed", path.toString(), result);
+      throw FileSystemException._fromOSError(
+          result, "Setting current working directory failed", path.toString());
     }
   }
 
@@ -81,7 +81,7 @@ class _Directory extends FileSystemEntity implements Directory {
   Future<bool> exists() {
     return _File._dispatchWithNamespace(
         _IOService.directoryExists, [null, _rawPath]).then((response) {
-      _checkForErrorResponse(response, "Exists failed");
+      _checkForErrorResponse(response, "Exists failed", path);
       return response == 1;
     });
   }
@@ -111,7 +111,7 @@ class _Directory extends FileSystemEntity implements Directory {
     } else {
       return _File._dispatchWithNamespace(
           _IOService.directoryCreate, [null, _rawPath]).then((response) {
-        _checkForErrorResponse(response, "Creation failed");
+        _checkForErrorResponse(response, "Creation failed", path);
         return this;
       });
     }
@@ -126,7 +126,7 @@ class _Directory extends FileSystemEntity implements Directory {
     }
     var result = _create(_Namespace._namespace, _rawPath);
     if (result is OSError) {
-      throw new FileSystemException("Creation failed", path, result);
+      throw FileSystemException._fromOSError(result, "Creation failed", path);
     }
   }
 
@@ -150,7 +150,7 @@ class _Directory extends FileSystemEntity implements Directory {
     return _File._dispatchWithNamespace(_IOService.directoryCreateTemp,
         [null, FileSystemEntity._toUtf8Array(fullPrefix)]).then((response) {
       _checkForErrorResponse(
-          response, "Creation of temporary directory failed");
+          response, "Creation of temporary directory failed", path);
       return Directory(response as String);
     });
   }
@@ -172,8 +172,8 @@ class _Directory extends FileSystemEntity implements Directory {
     var result = _createTemp(
         _Namespace._namespace, FileSystemEntity._toUtf8Array(fullPrefix));
     if (result is OSError) {
-      throw new FileSystemException(
-          "Creation of temporary directory failed", fullPrefix, result);
+      throw new FileSystemException._fromOSError(
+          result, "Creation of temporary directory failed", fullPrefix);
     }
     return new Directory(result);
   }
@@ -182,7 +182,7 @@ class _Directory extends FileSystemEntity implements Directory {
     return _File._dispatchWithNamespace(
             _IOService.directoryDelete, [null, _rawPath, recursive])
         .then((response) {
-      _checkForErrorResponse(response, "Deletion failed");
+      _checkForErrorResponse(response, "Deletion failed", path);
       return this;
     });
   }
@@ -190,14 +190,14 @@ class _Directory extends FileSystemEntity implements Directory {
   void _deleteSync({bool recursive = false}) {
     var result = _deleteNative(_Namespace._namespace, _rawPath, recursive);
     if (result is OSError) {
-      throw new FileSystemException("Deletion failed", path, result);
+      throw FileSystemException._fromOSError(result, "Deletion failed", path);
     }
   }
 
   Future<Directory> rename(String newPath) {
     return _File._dispatchWithNamespace(
         _IOService.directoryRename, [null, _rawPath, newPath]).then((response) {
-      _checkForErrorResponse(response, "Rename failed");
+      _checkForErrorResponse(response, "Rename failed", path);
       return new Directory(newPath);
     });
   }
@@ -207,7 +207,7 @@ class _Directory extends FileSystemEntity implements Directory {
     ArgumentError.checkNotNull(newPath, "newPath");
     var result = _rename(_Namespace._namespace, _rawPath, newPath);
     if (result is OSError) {
-      throw new FileSystemException("Rename failed", path, result);
+      throw FileSystemException._fromOSError(result, "Rename failed", path);
     }
     return new Directory(newPath);
   }
@@ -244,22 +244,6 @@ class _Directory extends FileSystemEntity implements Directory {
 
   String toString() => "Directory: '$path'";
 
-  /// If the [response] is an error, throws an [Exception] or an [Error].
-  void _checkForErrorResponse(Object? response, String message) {
-    if (response is List<Object?> && response[0] != _successResponse) {
-      switch (response[_errorResponseErrorType]) {
-        case _illegalArgumentResponse:
-          throw ArgumentError();
-        case _osErrorResponse:
-          var err = OSError(response[_osErrorResponseMessage] as String,
-              response[_osErrorResponseErrorCode] as int);
-          throw FileSystemException(message, path, err);
-        default:
-          throw AssertionError("Unknown error");
-      }
-    }
-  }
-
   // TODO(40614): Remove once non-nullability is sound.
   static T _checkNotNull<T>(T t, String name) {
     ArgumentError.checkNotNull(t, name);
@@ -430,8 +414,8 @@ class _AsyncDirectoryLister {
       } else if (errorPath is Uint8List) {
         errorPath = utf8.decode(errorPath, allowMalformed: true);
       }
-      controller.addError(new FileSystemException(
-          "Directory listing failed", errorPath as String, err));
+      controller.addError(FileSystemException._fromOSError(
+          err, "Directory listing failed", errorPath as String));
     } else {
       controller.addError(new FileSystemException("Internal error"));
     }
diff --git a/sdk/lib/io/file.dart b/sdk/lib/io/file.dart
index 0b532a3d111..6659cd1b4b1 100644
--- a/sdk/lib/io/file.dart
+++ b/sdk/lib/io/file.dart
@@ -418,6 +418,8 @@ abstract class File implements FileSystemEntity {
   ///
   /// * [FileMode.append]: same as [FileMode.write] except that the file is
   /// not truncated.
+  ///
+  /// Throws a [FileSystemException] if the operation fails.
   Future<RandomAccessFile> open({FileMode mode = FileMode.read});
 
   /// Synchronously opens the file for random access operations.
@@ -890,12 +892,42 @@ class FileSystemException implements IOException {
   ///
   /// The [message] and [path] path defaults to empty strings if omitted,
   /// and [osError] defaults to `null`.
-  @pragma("vm:entry-point")
   const FileSystemException([this.message = "", this.path = "", this.osError]);
 
-  String toString() {
+  /// Create a new file system exception based on an [OSError.errorCode].
+  ///
+  /// For example, if `errorCode == 2` then a [PathNotFoundException]
+  /// will be returned.
+  @pragma("vm:entry-point")
+  factory FileSystemException._fromOSError(
+      OSError err, String message, String? path) {
+    if (Platform.isWindows) {
+      switch (err.errorCode) {
+        case _errorFileNotFound:
+        case _errorPathNotFound:
+        case _errorInvalidDrive:
+        case _errorNoMoreFiles:
+        case _errorBadNetpath:
+        case _errorBadNetName:
+        case _errorBadPathName:
+        case _errorFilenameExedRange:
+          return PathNotFoundException(path!, err, message);
+        default:
+          return FileSystemException(message, path, err);
+      }
+    } else {
+      switch (err.errorCode) {
+        case _eNoEnt:
+          return PathNotFoundException(path!, err, message);
+        default:
+          return FileSystemException(message, path, err);
+      }
+    }
+  }
+
+  String _toStringHelper(String className) {
     StringBuffer sb = new StringBuffer();
-    sb.write("FileSystemException");
+    sb.write(className);
     if (message.isNotEmpty) {
       sb.write(": $message");
       if (path != null) {
@@ -914,6 +946,22 @@ class FileSystemException implements IOException {
     }
     return sb.toString();
   }
+
+  String toString() {
+    return _toStringHelper("FileSystemException");
+  }
+}
+
+/// Exception thrown when a file operation fails because a file or
+/// directory does not exist.
+class PathNotFoundException extends FileSystemException {
+  const PathNotFoundException(String path, OSError osError,
+      [String message = ""])
+      : super(message, path, osError);
+
+  String toString() {
+    return _toStringHelper("PathNotFoundException");
+  }
 }
 
 /// The "read" end of an [Pipe] created by [Pipe.create].
diff --git a/sdk/lib/io/file_impl.dart b/sdk/lib/io/file_impl.dart
index 688484e6873..c3a9a8d5b4a 100644
--- a/sdk/lib/io/file_impl.dart
+++ b/sdk/lib/io/file_impl.dart
@@ -626,7 +626,7 @@ class _File extends FileSystemEntity implements File {
 
   static throwIfError(Object result, String msg, String path) {
     if (result is OSError) {
-      throw new FileSystemException(msg, path, result);
+      throw FileSystemException._fromOSError(result, msg, path);
     }
   }
 
diff --git a/sdk/lib/io/link.dart b/sdk/lib/io/link.dart
index 5f730617430..477a3de48ee 100644
--- a/sdk/lib/io/link.dart
+++ b/sdk/lib/io/link.dart
@@ -251,23 +251,7 @@ class _Link extends FileSystemEntity implements Link {
 
   static throwIfError(Object? result, String msg, [String path = ""]) {
     if (result is OSError) {
-      throw new FileSystemException(msg, path, result);
-    }
-  }
-
-  /// If the [response] is an error, throws an [Exception] or an [Error].
-  void _checkForErrorResponse(Object? response, String message, String path) {
-    if (response is List<Object?> && response[0] != _successResponse) {
-      switch (response[_errorResponseErrorType]) {
-        case _illegalArgumentResponse:
-          throw ArgumentError();
-        case _osErrorResponse:
-          var err = OSError(response[_osErrorResponseMessage] as String,
-              response[_osErrorResponseErrorCode] as int);
-          throw FileSystemException(message, path, err);
-        default:
-          throw AssertionError("Unknown error");
-      }
+      throw FileSystemException._fromOSError(result, msg, path);
     }
   }
 }
diff --git a/tests/standalone/io/directory_error_test.dart b/tests/standalone/io/directory_error_test.dart
index 159d827548b..c00fbf67b79 100644
--- a/tests/standalone/io/directory_error_test.dart
+++ b/tests/standalone/io/directory_error_test.dart
@@ -15,7 +15,7 @@ Directory tempDir() {
 }
 
 bool checkCreateInNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Creation failed") != -1);
   if (Platform.operatingSystem == "linux") {
@@ -41,7 +41,7 @@ void testCreateInNonExistent(Directory temp, Function done) {
 }
 
 bool checkCreateTempInNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   if (Platform.operatingSystem == "linux") {
     Expect.equals(2, e.osError.errorCode);
@@ -67,7 +67,7 @@ void testCreateTempInNonExistent(Directory temp, Function done) {
 }
 
 bool checkDeleteNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   // File not not found has error code 2 on all supported platforms.
   Expect.equals(2, e.osError.errorCode);
@@ -87,7 +87,7 @@ void testDeleteNonExistent(Directory temp, Function done) {
 }
 
 bool checkDeleteRecursivelyNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Deletion failed") != -1);
   // File not not found has error code 2 on all supported platforms.
@@ -109,7 +109,7 @@ void testDeleteRecursivelyNonExistent(Directory temp, Function done) {
 }
 
 bool checkListNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Directory listing failed") != -1);
   if (Platform.operatingSystem == "linux") {
@@ -141,12 +141,12 @@ void testRenameNonExistent(Directory temp, Function done) {
   Directory nonExistent = new Directory("${temp.path}/nonExistent");
   var newPath = "${temp.path}/nonExistent2";
   Expect.throws(
-      () => nonExistent.renameSync(newPath), (e) => e is FileSystemException);
+      () => nonExistent.renameSync(newPath), (e) => e is PathNotFoundException);
   var renameDone = nonExistent.rename(newPath);
   renameDone
       .then((ignore) => Expect.fail('rename non existent'))
       .catchError((error) {
-    Expect.isTrue(error is FileSystemException);
+    Expect.isTrue(error is PathNotFoundException);
     done();
   });
 }
diff --git a/tests/standalone/io/directory_list_nonexistent_test.dart b/tests/standalone/io/directory_list_nonexistent_test.dart
index c3e92f1ee69..35866c1e476 100644
--- a/tests/standalone/io/directory_list_nonexistent_test.dart
+++ b/tests/standalone/io/directory_list_nonexistent_test.dart
@@ -16,9 +16,9 @@ void testListNonExistent() {
   asyncStart();
   Directory.systemTemp.createTemp('dart_directory_list_nonexistent').then((d) {
     d.delete().then((ignore) {
-      Expect.throws(() => d.listSync(), (e) => e is FileSystemException);
+      Expect.throws(() => d.listSync(), (e) => e is PathNotFoundException);
       Expect.throws(
-          () => d.listSync(recursive: true), (e) => e is FileSystemException);
+          () => d.listSync(recursive: true), (e) => e is PathNotFoundException);
       asyncEnd();
     });
   });
diff --git a/tests/standalone/io/directory_test.dart b/tests/standalone/io/directory_test.dart
index c6f6e8129a7..1053368d0ab 100644
--- a/tests/standalone/io/directory_test.dart
+++ b/tests/standalone/io/directory_test.dart
@@ -162,7 +162,7 @@ class DirectoryTest {
       future.then((ignore) {
         Expect.fail("Deletion of non-existing directory should fail");
       }).catchError((error) {
-        Expect.isTrue(error is FileSystemException);
+        Expect.isTrue(error is PathNotFoundException);
       });
     }
 
diff --git a/tests/standalone/io/file_error_test.dart b/tests/standalone/io/file_error_test.dart
index 2050e23b098..c4e3e686e8f 100644
--- a/tests/standalone/io/file_error_test.dart
+++ b/tests/standalone/io/file_error_test.dart
@@ -15,7 +15,7 @@ Directory tempDir() {
 }
 
 bool checkCannotOpenFileException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Cannot open file") != -1);
   if (Platform.operatingSystem == "linux") {
@@ -29,7 +29,7 @@ bool checkCannotOpenFileException(e) {
 }
 
 bool checkNonExistentFileSystemException(e, str) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf(str) != -1);
   // File not not found has error code 2 on all supported platforms.
diff --git a/tests/standalone/io/file_system_watcher_test.dart b/tests/standalone/io/file_system_watcher_test.dart
index e629e56596d..d7e9e25a86b 100644
--- a/tests/standalone/io/file_system_watcher_test.dart
+++ b/tests/standalone/io/file_system_watcher_test.dart
@@ -311,7 +311,7 @@ void testWatchNonExisting() {
     Expect.fail('unexpected error');
   }, onError: (e) {
     asyncEnd();
-    Expect.isTrue(e is FileSystemException);
+    Expect.isTrue(e is PathNotFoundException);
   });
 }
 
diff --git a/tests/standalone/io/link_test.dart b/tests/standalone/io/link_test.dart
index 3e36111ec06..43e816a2780 100644
--- a/tests/standalone/io/link_test.dart
+++ b/tests/standalone/io/link_test.dart
@@ -241,7 +241,7 @@ void testLinkErrorSync() {
   Expect.throws(
       () => new Link('some-dir-that-doent exist/some link file/bla/fisk')
           .createSync('bla bla bla/b lalal/blfir/sdfred/es'),
-      (e) => e is FileSystemException);
+      (e) => e is PathNotFoundException);
 }
 
 checkExists(String filePath) => Expect.isTrue(new File(filePath).existsSync());
diff --git a/tests/standalone_2/io/directory_error_test.dart b/tests/standalone_2/io/directory_error_test.dart
index 5cdd73b4fbc..1a264d43bf1 100644
--- a/tests/standalone_2/io/directory_error_test.dart
+++ b/tests/standalone_2/io/directory_error_test.dart
@@ -17,7 +17,7 @@ Directory tempDir() {
 }
 
 bool checkCreateInNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Creation failed") != -1);
   if (Platform.operatingSystem == "linux") {
@@ -43,7 +43,7 @@ void testCreateInNonExistent(Directory temp, Function done) {
 }
 
 bool checkCreateTempInNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   if (Platform.operatingSystem == "linux") {
     Expect.equals(2, e.osError.errorCode);
@@ -68,7 +68,7 @@ void testCreateTempInNonExistent(Directory temp, Function done) {
 }
 
 bool checkDeleteNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   // File not not found has error code 2 on all supported platforms.
   Expect.equals(2, e.osError.errorCode);
@@ -88,7 +88,7 @@ void testDeleteNonExistent(Directory temp, Function done) {
 }
 
 bool checkDeleteRecursivelyNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Deletion failed") != -1);
   // File not not found has error code 2 on all supported platforms.
@@ -109,7 +109,7 @@ void testDeleteRecursivelyNonExistent(Directory temp, Function done) {
 }
 
 bool checkListNonExistentFileSystemException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Directory listing failed") != -1);
   if (Platform.operatingSystem == "linux") {
@@ -141,12 +141,12 @@ void testRenameNonExistent(Directory temp, Function done) {
   Directory nonExistent = new Directory("${temp.path}/nonExistent");
   var newPath = "${temp.path}/nonExistent2";
   Expect.throws(
-      () => nonExistent.renameSync(newPath), (e) => e is FileSystemException);
+      () => nonExistent.renameSync(newPath), (e) => e is PathNotFoundException);
   var renameDone = nonExistent.rename(newPath);
   renameDone
       .then((ignore) => Expect.fail('rename non existent'))
       .catchError((error) {
-    Expect.isTrue(error is FileSystemException);
+    Expect.isTrue(error is PathNotFoundException);
     done();
   });
 }
diff --git a/tests/standalone_2/io/directory_list_nonexistent_test.dart b/tests/standalone_2/io/directory_list_nonexistent_test.dart
index ab182f24153..51adb2f78b3 100644
--- a/tests/standalone_2/io/directory_list_nonexistent_test.dart
+++ b/tests/standalone_2/io/directory_list_nonexistent_test.dart
@@ -18,9 +18,9 @@ void testListNonExistent() {
   asyncStart();
   Directory.systemTemp.createTemp('dart_directory_list_nonexistent').then((d) {
     d.delete().then((ignore) {
-      Expect.throws(() => d.listSync(), (e) => e is FileSystemException);
+      Expect.throws(() => d.listSync(), (e) => e is PathNotFoundException);
       Expect.throws(
-          () => d.listSync(recursive: true), (e) => e is FileSystemException);
+          () => d.listSync(recursive: true), (e) => e is PathNotFoundException);
       asyncEnd();
     });
   });
diff --git a/tests/standalone_2/io/directory_test.dart b/tests/standalone_2/io/directory_test.dart
index f0dad532599..3a440ac705d 100644
--- a/tests/standalone_2/io/directory_test.dart
+++ b/tests/standalone_2/io/directory_test.dart
@@ -164,7 +164,7 @@ class DirectoryTest {
       future.then((ignore) {
         Expect.fail("Deletion of non-existing directory should fail");
       }).catchError((error) {
-        Expect.isTrue(error is FileSystemException);
+        Expect.isTrue(error is PathNotFoundException);
       });
     }
 
diff --git a/tests/standalone_2/io/file_error_test.dart b/tests/standalone_2/io/file_error_test.dart
index d52f2ee9743..0c933f646ca 100644
--- a/tests/standalone_2/io/file_error_test.dart
+++ b/tests/standalone_2/io/file_error_test.dart
@@ -17,7 +17,7 @@ Directory tempDir() {
 }
 
 bool checkCannotOpenFileException(e) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Cannot open file") != -1);
   if (Platform.operatingSystem == "linux") {
@@ -31,7 +31,7 @@ bool checkCannotOpenFileException(e) {
 }
 
 bool checkNonExistentFileSystemException(e, str) {
-  Expect.isTrue(e is FileSystemException);
+  Expect.isTrue(e is PathNotFoundException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf(str) != -1);
   // File not not found has error code 2 on all supported platforms.
diff --git a/tests/standalone_2/io/file_system_watcher_test.dart b/tests/standalone_2/io/file_system_watcher_test.dart
index b3e79dbde58..9a4d3d7d22e 100644
--- a/tests/standalone_2/io/file_system_watcher_test.dart
+++ b/tests/standalone_2/io/file_system_watcher_test.dart
@@ -312,7 +312,7 @@ void testWatchNonExisting() {
     Expect.fail('unexpected error');
   }, onError: (e) {
     asyncEnd();
-    Expect.isTrue(e is FileSystemException);
+    Expect.isTrue(e is PathNotFoundException);
   });
 }
 
diff --git a/tests/standalone_2/io/link_test.dart b/tests/standalone_2/io/link_test.dart
index e2793b0eceb..c01aac5b86b 100644
--- a/tests/standalone_2/io/link_test.dart
+++ b/tests/standalone_2/io/link_test.dart
@@ -243,7 +243,7 @@ void testLinkErrorSync() {
   Expect.throws(
       () => new Link('some-dir-that-doent exist/some link file/bla/fisk')
           .createSync('bla bla bla/b lalal/blfir/sdfred/es'),
-      (e) => e is FileSystemException);
+      (e) => e is PathNotFoundException);
 }
 
 checkExists(String filePath) => Expect.isTrue(new File(filePath).existsSync());