diff --git a/src/Common/src/NativeMethods.cs b/src/Common/src/NativeMethods.cs
index b4a24211b69..afcaad845ec 100644
--- a/src/Common/src/NativeMethods.cs
+++ b/src/Common/src/NativeMethods.cs
@@ -2007,12 +2007,11 @@ public PICTDESCemf(System.Drawing.Imaging.Metafile metafile)
             }
         }
 
-        [StructLayout(LayoutKind.Sequential)]
-        public class USEROBJECTFLAGS
+        public struct USEROBJECTFLAGS
         {
-            public int fInherit = 0;
-            public int fReserved = 0;
-            public int dwFlags = 0;
+            public int fInherit;
+            public int fReserved;
+            public int dwFlags;
         }
 
         [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
diff --git a/src/Common/src/UnsafeNativeMethods.cs b/src/Common/src/UnsafeNativeMethods.cs
index 53a95e4b1c8..8a27a07ea94 100644
--- a/src/Common/src/UnsafeNativeMethods.cs
+++ b/src/Common/src/UnsafeNativeMethods.cs
@@ -1104,7 +1104,7 @@ public static bool TrySystemParametersInfoForDpi(int nAction, int nParam, [In, O
         public static extern IntPtr GetProcessWindowStation();
         [DllImport(ExternDll.User32, SetLastError = true)]
 
-        public static extern bool GetUserObjectInformation(HandleRef hObj, int nIndex, [MarshalAs(UnmanagedType.LPStruct)] NativeMethods.USEROBJECTFLAGS pvBuffer, int nLength, ref int lpnLengthNeeded);
+        public static extern bool GetUserObjectInformation(HandleRef hObj, int nIndex, ref NativeMethods.USEROBJECTFLAGS pvBuffer, int nLength, ref int lpnLengthNeeded);
         [DllImport(ExternDll.User32, ExactSpelling = true, CharSet = CharSet.Auto)]
 
         public static extern int ClientToScreen(HandleRef hWnd, [In, Out] NativeMethods.POINT pt);
diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/SystemInformation.cs b/src/System.Windows.Forms/src/System/Windows/Forms/SystemInformation.cs
index 82470af3312..b6451c345f7 100644
--- a/src/System.Windows.Forms/src/System/Windows/Forms/SystemInformation.cs
+++ b/src/System.Windows.Forms/src/System/Windows/Forms/SystemInformation.cs
@@ -795,7 +795,7 @@ public static string ComputerName
         /// Gets a value indicating whether the current process is running in user
         /// interactive mode.
         /// </summary>
-        public static bool UserInteractive
+        public unsafe static bool UserInteractive
         {
             get
             {
@@ -807,7 +807,7 @@ public static bool UserInteractive
                     int lengthNeeded = 0;
                     NativeMethods.USEROBJECTFLAGS flags = new NativeMethods.USEROBJECTFLAGS();
 
-                    if (UnsafeNativeMethods.GetUserObjectInformation(new HandleRef(null, hwinsta), NativeMethods.UOI_FLAGS, flags, Marshal.SizeOf(flags), ref lengthNeeded))
+                    if (UnsafeNativeMethods.GetUserObjectInformation(new HandleRef(null, hwinsta), NativeMethods.UOI_FLAGS, ref flags, sizeof(NativeMethods.USEROBJECTFLAGS), ref lengthNeeded))
                     {
                         if ((flags.dwFlags & NativeMethods.WSF_VISIBLE) == 0)
                         {