diff --git a/Lib/test/test_exception_hierarchy.py b/Lib/test/test_exception_hierarchy.py
@@ -5,6 +5,7 @@
 import unittest
 import errno
 from errno import EEXIST
+import sys
 
 
 class SubOSError(OSError):
@@ -130,8 +131,8 @@ def test_windows_error(self):
         else:
             self.assertNotIn('winerror', dir(OSError))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.skip("TODO: RUSTPYTHON")
+    @unittest.skipIf(sys.platform == 'win32', 'winerror not filled yet')
     def test_posix_error(self):
         e = OSError(EEXIST, "File already exists", "foo.txt")
         self.assertEqual(e.errno, EEXIST)

diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py
@@ -391,8 +391,6 @@ class PyAutoFileTests(AutoFileTests, unittest.TestCase):
     FileIO = _pyio.FileIO
     modulename = '_pyio'
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def testOpendir(self):
         super().testOpendir()
 

diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
@@ -1547,8 +1547,6 @@ def test_failed_child_execute_fd_leak(self):
         fds_after_exception = os.listdir(fd_directory)
         self.assertEqual(fds_before_popen, fds_after_exception)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     @unittest.skipIf(mswindows, "behavior currently not supported on Windows")
     def test_file_not_found_includes_filename(self):
         with self.assertRaises(FileNotFoundError) as c:

diff --git a/extra_tests/snippets/builtin_exceptions.py b/extra_tests/snippets/builtin_exceptions.py
@@ -264,6 +264,40 @@ class SubError(MyError):
 assert OSError(1, 2).errno
 assert OSError(1, 2).strerror
 
+
+# OSError Unexpected number of arguments
+w = OSError()
+assert w.errno == None
+assert not sys.platform.startswith("win") or w.winerror == None
+assert w.strerror == None
+assert w.filename == None
+assert w.filename2 == None
+assert str(w) == ""
+
+w = OSError(0)
+assert w.errno == None
+assert not sys.platform.startswith("win") or w.winerror == None
+assert w.strerror == None
+assert w.filename == None
+assert w.filename2 == None
+assert str(w) == "0"
+
+w = OSError('foo')
+assert w.errno == None
+assert not sys.platform.startswith("win") or w.winerror == None
+assert w.strerror == None
+assert w.filename == None
+assert w.filename2 == None
+assert str(w) == "foo"
+
+w = OSError('a', 'b', 'c', 'd', 'e', 'f')
+assert w.errno == None
+assert not sys.platform.startswith("win") or w.winerror == None
+assert w.strerror == None
+assert w.filename == None
+assert w.filename2 == None
+assert str(w) == "('a', 'b', 'c', 'd', 'e', 'f')"
+
 # Custom `__new__` and `__init__`:
 assert ImportError.__init__.__qualname__ == 'ImportError.__init__'
 assert ImportError(name='a').name == 'a'

diff --git a/vm/src/exceptions.rs b/vm/src/exceptions.rs
@@ -752,13 +752,22 @@ impl ExceptionZoo {
         let errno_getter =
             ctx.new_readonly_getset("errno", excs.os_error, |exc: PyBaseExceptionRef| {
                 let args = exc.args();
-                args.get(0).filter(|_| args.len() > 1).cloned()
+                args.get(0)
+                    .filter(|_| args.len() > 1 && args.len() <= 5)
+                    .cloned()
+            });
+        let strerror_getter =
+            ctx.new_readonly_getset("strerror", excs.os_error, |exc: PyBaseExceptionRef| {
+                let args = exc.args();
+                args.get(1)
+                    .filter(|_| args.len() >= 2 && args.len() <= 5)
+                    .cloned()
             });
         extend_exception!(PyOSError, ctx, excs.os_error, {
             // POSIX exception code
             "errno" => errno_getter.clone(),
             // exception strerror
-            "strerror" => ctx.new_readonly_getset("strerror", excs.os_error, make_arg_getter(1)),
+            "strerror" => strerror_getter.clone(),
             // exception filename
             "filename" => ctx.none(),
             // second exception filename
@@ -1260,15 +1269,15 @@ pub(super) mod types {
         os_error,
         "Base class for I/O related errors.",
         os_error_new,
-        base_exception_init,
+        os_error_init,
     }
     #[cfg(not(target_arch = "wasm32"))]
     fn os_error_optional_new(
         args: Vec<PyObjectRef>,
         vm: &VirtualMachine,
     ) -> Option<PyBaseExceptionRef> {
         let len = args.len();
-        if len >= 2 {
+        if (2..=5).contains(&len) {
             let errno = &args[0];
             errno
                 .payload_if_subclass::<PyInt>(vm)
@@ -1297,9 +1306,18 @@ pub(super) mod types {
     fn os_error_new(cls: PyTypeRef, args: FuncArgs, vm: &VirtualMachine) -> PyResult {
         PyBaseException::slot_new(cls, args, vm)
     }
+    fn os_error_init(zelf: PyObjectRef, args: FuncArgs, vm: &VirtualMachine) -> PyResult<()> {
+        let len = args.args.len();
+        let mut new_args = args;
+        if (3..=5).contains(&len) {
+            zelf.set_attr("filename", new_args.args[2].clone(), vm)?;
+            if len == 5 {
+                zelf.set_attr("filename2", new_args.args[4].clone(), vm)?;
+            }
 
-    fn base_exception_init(zelf: PyObjectRef, args: FuncArgs, vm: &VirtualMachine) -> PyResult<()> {
-        PyBaseException::init(zelf, args, vm)
+            new_args.args.truncate(2);
+        }
+        PyBaseException::init(zelf, new_args, vm)
     }
 
     define_exception! {