diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py
index 448ea2325fe..ed96be53cca 100644
--- a/Lib/test/test_mmap.py
+++ b/Lib/test/test_mmap.py
@@ -867,7 +867,6 @@ def test_resize_fails_if_mapping_held_elsewhere(self):
         finally:
             f.close()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     @unittest.skipUnless(os.name == 'nt', 'requires Windows')
     def test_resize_succeeds_with_error_for_second_named_mapping(self):
         """If a more than one mapping exists of the same name, none of them can
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 824c636dfd1..2ba98616ea6 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1903,7 +1903,6 @@ def test_run_with_pathlike_path_and_arguments(self):
         res = subprocess.run(args)
         self.assertEqual(res.returncode, 57)
 
-    @unittest.skipIf(mswindows, "TODO: RUSTPYTHON; empty env block fails nondeterministically")
     @unittest.skipUnless(mswindows, "Maybe test trigger a leak on Ubuntu")
     def test_run_with_an_empty_env(self):
         # gh-105436: fix subprocess.run(..., env={}) broken on Windows
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index 89987aeba6e..71c2f7512b1 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -878,7 +878,6 @@ def test_sys_flags_no_instantiation(self):
     def test_sys_version_info_no_instantiation(self):
         self.assert_raise_on_new_sys_type(sys.version_info)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; TypeError not raised for getwindowsversion instantiation
     def test_sys_getwindowsversion_no_instantiation(self):
         # Skip if not being run on Windows.
         test.support.get_attribute(sys, "getwindowsversion")
diff --git a/crates/stdlib/src/mmap.rs b/crates/stdlib/src/mmap.rs
index d441a3dd887..a99d0cc131d 100644
--- a/crates/stdlib/src/mmap.rs
+++ b/crates/stdlib/src/mmap.rs
@@ -1204,7 +1204,7 @@ mod mmap {
 
             // Check if this is a Named mmap - these cannot be resized
             if let Some(MmapObj::Named(_)) = mmap_guard.as_ref() {
-                return Err(vm.new_system_error("mmap: cannot resize a named memory mapping"));
+                return Err(vm.new_os_error("mmap: cannot resize a named memory mapping"));
             }
 
             let is_anonymous = handle == INVALID_HANDLE_VALUE as isize;
diff --git a/crates/vm/src/stdlib/_winapi.rs b/crates/vm/src/stdlib/_winapi.rs
index 36113f054da..fe2e752b99f 100644
--- a/crates/vm/src/stdlib/_winapi.rs
+++ b/crates/vm/src/stdlib/_winapi.rs
@@ -445,6 +445,11 @@ mod _winapi {
         for (_, entry) in entries {
             out.push(entry);
         }
+        // Each entry ends with \0, so one more \0 terminates the block.
+        // For empty env, we need \0\0 as a valid empty environment block.
+        if out.is_empty() {
+            out.push_str("\0");
+        }
         out.push_str("\0");
         Ok(out.into_vec())
     }
diff --git a/crates/vm/src/stdlib/errno.rs b/crates/vm/src/stdlib/errno.rs
index 8e4efbaafe9..d7a0a222a76 100644
--- a/crates/vm/src/stdlib/errno.rs
+++ b/crates/vm/src/stdlib/errno.rs
@@ -39,12 +39,11 @@ pub mod errors {
             WSAENOMORE, WSAENOPROTOOPT, WSAENOTCONN, WSAENOTEMPTY, WSAENOTSOCK, WSAEOPNOTSUPP,
             WSAEPFNOSUPPORT, WSAEPROCLIM, WSAEPROTONOSUPPORT, WSAEPROTOTYPE,
             WSAEPROVIDERFAILEDINIT, WSAEREFUSED, WSAEREMOTE, WSAESHUTDOWN, WSAESOCKTNOSUPPORT,
-            WSAESTALE, WSAETIMEDOUT, WSAETOOMANYREFS, WSAEUSERS, WSAEWOULDBLOCK, WSAHOST_NOT_FOUND,
-            WSAID_ACCEPTEX, WSAID_CONNECTEX, WSAID_DISCONNECTEX, WSAID_GETACCEPTEXSOCKADDRS,
-            WSAID_TRANSMITFILE, WSAID_TRANSMITPACKETS, WSAID_WSAPOLL, WSAID_WSARECVMSG, WSANO_DATA,
-            WSANO_RECOVERY, WSANOTINITIALISED, WSAPROTOCOL_LEN, WSASERVICE_NOT_FOUND,
-            WSASYS_STATUS_LEN, WSASYSCALLFAILURE, WSASYSNOTREADY, WSATRY_AGAIN, WSATYPE_NOT_FOUND,
-            WSAVERNOTSUPPORTED,
+            WSAESTALE, WSAETIMEDOUT, WSAETOOMANYREFS, WSAEUSERS, WSAEWOULDBLOCK, WSAID_ACCEPTEX,
+            WSAID_CONNECTEX, WSAID_DISCONNECTEX, WSAID_GETACCEPTEXSOCKADDRS, WSAID_TRANSMITFILE,
+            WSAID_TRANSMITPACKETS, WSAID_WSAPOLL, WSAID_WSARECVMSG, WSANO_DATA, WSANO_RECOVERY,
+            WSANOTINITIALISED, WSAPROTOCOL_LEN, WSASERVICE_NOT_FOUND, WSASYS_STATUS_LEN,
+            WSASYSCALLFAILURE, WSASYSNOTREADY, WSATRY_AGAIN, WSATYPE_NOT_FOUND, WSAVERNOTSUPPORTED,
         },
     };
     #[cfg(windows)]
@@ -64,8 +63,6 @@ pub mod errors {
         ETIMEDOUT, ETOOMANYREFS, EUSERS, EWOULDBLOCK,
         // TODO: EBADF should be here once winerrs are translated to errnos but it messes up some things atm
     }
-    #[cfg(windows)]
-    pub const WSAHOS: i32 = WSAHOST_NOT_FOUND;
 }
 
 #[cfg(any(unix, windows, target_os = "wasi"))]
@@ -566,7 +563,7 @@ const ERROR_CODES: &[(&str, i32)] = &[
     e!(cfg(windows), WSAEDISCON),
     e!(cfg(windows), WSAEINTR),
     e!(cfg(windows), WSAEPROTOTYPE),
-    e!(cfg(windows), WSAHOS),
+    // TODO: e!(cfg(windows), WSAHOS),
     e!(cfg(windows), WSAEADDRINUSE),
     e!(cfg(windows), WSAEADDRNOTAVAIL),
     e!(cfg(windows), WSAEALREADY),
diff --git a/crates/vm/src/stdlib/sys.rs b/crates/vm/src/stdlib/sys.rs
index 33325c9dc60..72379494ddb 100644
--- a/crates/vm/src/stdlib/sys.rs
+++ b/crates/vm/src/stdlib/sys.rs
@@ -1807,7 +1807,12 @@ mod sys {
 
     #[cfg(windows)]
     #[pyclass(with(PyStructSequence))]
-    impl PyWindowsVersion {}
+    impl PyWindowsVersion {
+        #[pyslot]
+        fn slot_new(_cls: PyTypeRef, _args: FuncArgs, vm: &VirtualMachine) -> PyResult {
+            Err(vm.new_type_error("cannot create 'sys.getwindowsversion' instances"))
+        }
+    }
 
     #[derive(Debug)]
     #[pystruct_sequence_data(try_from_object)]