diff --git a/eng/Versions.props b/eng/Versions.props
index 83714a95f89..6bec72a335e 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -16,7 +16,7 @@
   <!-- Below have no corresponding entries in Versions.Details.XML because they are not updated via Maestro -->
   <PropertyGroup>
     <SystemRuntimeCompilerServicesUnsafePackageVersion>6.1.2</SystemRuntimeCompilerServicesUnsafePackageVersion>
-    <MicrosoftWindowsCsWin32PackageVersion>0.3.151</MicrosoftWindowsCsWin32PackageVersion>
+    <MicrosoftWindowsCsWin32PackageVersion>0.3.287</MicrosoftWindowsCsWin32PackageVersion>
   </PropertyGroup>
 
   <!-- Docs / Intellisense -->
diff --git a/src/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.cs b/src/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.cs
index 4437bb3fae1..da5c8bf0e7d 100644
--- a/src/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.cs
+++ b/src/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.cs
@@ -324,7 +324,7 @@ public void CopyToHdevmode(IntPtr hdevmode)
             {
                 int result = PInvoke.DocumentProperties(
                     HWND.Null,
-                    HANDLE.Null,
+                    global::Windows.Win32.Graphics.Printing.PRINTER_HANDLE.Null,
                     n,
                     devmode,
                     devmode,
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/IComIID.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/IComIID.cs
deleted file mode 100644
index ae2a611c7ad..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/IComIID.cs
+++ /dev/null
@@ -1,20 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32;
-
-/// <summary>
-///  Common interface for COM interface wrapping structs.
-/// </summary>
-/// <remarks>
-///  <para>
-///   On .NET 6 and later, this is provided by CSWin32 as an abstract static.
-///  </para>
-/// </remarks>
-internal interface IComIID
-{
-    /// <summary>
-    ///  The identifier (IID) GUID for this interface.
-    /// </summary>
-    ref readonly Guid Guid { get; }
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IAdviseSink.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IAdviseSink.cs
deleted file mode 100644
index e404d72924b..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IAdviseSink.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IAdviseSink : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IDataObject.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IDataObject.cs
deleted file mode 100644
index 4e328766ee6..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IDataObject.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IDataObject : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IEnumFORMATETC.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IEnumFORMATETC.cs
deleted file mode 100644
index 180e6be0aa4..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IEnumFORMATETC.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IEnumFORMATETC : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IEnumSTATDATA.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IEnumSTATDATA.cs
deleted file mode 100644
index 403e7637467..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IEnumSTATDATA.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IEnumSTATDATA : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IGlobalInterfaceTable.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IGlobalInterfaceTable.cs
deleted file mode 100644
index 50c5ffcb0ff..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IGlobalInterfaceTable.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IGlobalInterfaceTable : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IStream.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IStream.cs
deleted file mode 100644
index 596fd686acb..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IStream.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IStream : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/ITypeInfo.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/ITypeInfo.cs
deleted file mode 100644
index dd182c58599..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/ITypeInfo.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct ITypeInfo : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/ITypeLib.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/ITypeLib.cs
deleted file mode 100644
index 3d46bc1a848..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/ITypeLib.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct ITypeLib : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IUnknown.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IUnknown.cs
deleted file mode 100644
index ce6d2f8b2d0..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Com/IUnknown.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Com;
-
-internal partial struct IUnknown : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Ole/IDropTarget.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Ole/IDropTarget.cs
deleted file mode 100644
index e83ec0be325..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/System/Ole/IDropTarget.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.System.Ole;
-
-internal partial struct IDropTarget : IComIID
-{
-    readonly ref readonly Guid IComIID.Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/UI/Shell/IDragSourceHelper2.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/UI/Shell/IDragSourceHelper2.cs
deleted file mode 100644
index f26f13366d3..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/UI/Shell/IDragSourceHelper2.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.UI.Shell;
-
-internal partial struct IDragSourceHelper2 : IComIID
-{
-    public readonly ref readonly Guid Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/UI/Shell/IDropTargetHelper.cs b/src/System.Private.Windows.Core/src/Framework/Windows/Win32/UI/Shell/IDropTargetHelper.cs
deleted file mode 100644
index 705a0ae874c..00000000000
--- a/src/System.Private.Windows.Core/src/Framework/Windows/Win32/UI/Shell/IDropTargetHelper.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace Windows.Win32.UI.Shell;
-
-internal partial struct IDropTargetHelper : IComIID
-{
-    public readonly ref readonly Guid Guid => ref Unsafe.AsRef(in IID_Guid);
-}
diff --git a/src/System.Private.Windows.Core/src/Microsoft.Private.Windows.Core.csproj b/src/System.Private.Windows.Core/src/Microsoft.Private.Windows.Core.csproj
index 8a9e6ecc3b8..028ddf0be71 100644
--- a/src/System.Private.Windows.Core/src/Microsoft.Private.Windows.Core.csproj
+++ b/src/System.Private.Windows.Core/src/Microsoft.Private.Windows.Core.csproj
@@ -15,9 +15,10 @@
 
     <!--
       CS3016: We don't care about CLS compliance since everything here is internal and we want to match native types.
+      CS3021: CsWin32-generated COM structs carry [CLSCompliant(false)]; we don't mark the assembly CLS-compliant.
       SYSLIB5005: System.Formats.Nrbf is experimental
     -->
-    <NoWarn>$(NoWarn);CS3016;SYSLIB5005</NoWarn>
+    <NoWarn>$(NoWarn);CS3016;CS3021;SYSLIB5005</NoWarn>
 
     <!--
       CA1822: The codebase contains a number of extension types where they reference instance state, but the analyzer
diff --git a/src/System.Private.Windows.Core/src/System.Private.Windows.Core.csproj b/src/System.Private.Windows.Core/src/System.Private.Windows.Core.csproj
index a6262e7f553..fcb378490ca 100644
--- a/src/System.Private.Windows.Core/src/System.Private.Windows.Core.csproj
+++ b/src/System.Private.Windows.Core/src/System.Private.Windows.Core.csproj
@@ -15,9 +15,10 @@
 
     <!--
       CS3016: We don't care about CLS compliance since everything here is internal and we want to match native types.
+      CS3021: CsWin32-generated COM structs carry [CLSCompliant(false)]; we don't mark the assembly CLS-compliant.
       SYSLIB5005: System.Formats.Nrbf is experimental
     -->
-    <NoWarn>$(NoWarn);CS3016;SYSLIB5005</NoWarn>
+    <NoWarn>$(NoWarn);CS3016;CS3021;SYSLIB5005</NoWarn>
 
     <!--
       CA1822: The codebase contains a number of extension types where they reference instance state, but the analyzer
diff --git a/src/System.Private.Windows.Core/src/System/Private/Windows/Ole/Composition.ManagedToNativeAdapter.cs b/src/System.Private.Windows.Core/src/System/Private/Windows/Ole/Composition.ManagedToNativeAdapter.cs
index b2dd42b8fb0..750a6b457fe 100644
--- a/src/System.Private.Windows.Core/src/System/Private/Windows/Ole/Composition.ManagedToNativeAdapter.cs
+++ b/src/System.Private.Windows.Core/src/System/Private/Windows/Ole/Composition.ManagedToNativeAdapter.cs
@@ -375,7 +375,7 @@ static HRESULT SaveFileListToHGLOBAL(HGLOBAL hglobal, string[] files)
 
             static HRESULT SaveDbcsToHGLOBAL(HGLOBAL hglobal, string value)
             {
-                int byteCount = PInvokeCore.WideCharToMultiByte(PInvokeCore.CP_ACP, 0, value, value.Length, null, 0, null, null);
+                int byteCount = PInvokeCore.WideCharToMultiByte(PInvokeCore.CP_ACP, 0, value, value.Length, null, 0, null);
 
                 using GlobalBuffer buffer = new(hglobal, (uint)byteCount + 1);
                 if (buffer.Status.Failed)
@@ -383,7 +383,7 @@ static HRESULT SaveDbcsToHGLOBAL(HGLOBAL hglobal, string value)
                     return buffer.Status;
                 }
 
-                PInvokeCore.WideCharToMultiByte(PInvokeCore.CP_ACP, 0, value, value.Length, (PSTR)buffer.Pointer, byteCount, null, null);
+                PInvokeCore.WideCharToMultiByte(PInvokeCore.CP_ACP, 0, value, value.Length, (PSTR)buffer.Pointer, byteCount, null);
 
                 // Null terminate.
                 buffer.AsSpan()[byteCount] = 0;
diff --git a/src/System.Windows.Forms.Primitives/src/Microsoft/VisualStudio/Shell/IVsPerPropertyBrowsing.cs b/src/System.Windows.Forms.Primitives/src/Microsoft/VisualStudio/Shell/IVsPerPropertyBrowsing.cs
index 11bec9000c4..7436168b3b6 100644
--- a/src/System.Windows.Forms.Primitives/src/Microsoft/VisualStudio/Shell/IVsPerPropertyBrowsing.cs
+++ b/src/System.Windows.Forms.Primitives/src/Microsoft/VisualStudio/Shell/IVsPerPropertyBrowsing.cs
@@ -180,7 +180,7 @@ HRESULT IsPropertyReadOnly(
         ///  Returns the class name for this object. The class name is the non-bolded text that appears in the properties
         ///  window selection combo. Returning any result other than <see cref="HRESULT.S_OK"/> will cause the default to
         ///  be used. The default is the name string from a call to
-        ///  <see cref="ITypeInfo.GetDocumentation(int, BSTR*, BSTR*, out uint, BSTR*)"/> with <see cref="PInvoke.MEMBERID_NIL"/>.
+        ///  <see cref="ITypeInfo.GetDocumentation(int, BSTR*, BSTR*, uint*, BSTR*)"/> with <see cref="PInvoke.MEMBERID_NIL"/>.
         /// </summary>
         [PreserveSig]
         HRESULT GetClassName(
diff --git a/src/System.Windows.Forms.Primitives/src/NativeMethods.txt b/src/System.Windows.Forms.Primitives/src/NativeMethods.txt
index 6f45368c470..a56634792b1 100644
--- a/src/System.Windows.Forms.Primitives/src/NativeMethods.txt
+++ b/src/System.Windows.Forms.Primitives/src/NativeMethods.txt
@@ -67,6 +67,8 @@ DestroyAcceleratorTable
 DestroyCursor
 DestroyMenu
 DestroyWindow
+DFC_TYPE
+DFCS_STATE
 DISPATCH_CONSTRUCT
 DISPATCH_FLAGS
 DispatchMessage
diff --git a/src/System.Windows.Forms.Primitives/src/System.Windows.Forms.Primitives.csproj b/src/System.Windows.Forms.Primitives/src/System.Windows.Forms.Primitives.csproj
index 57a1cac1d96..53ee3fec278 100644
--- a/src/System.Windows.Forms.Primitives/src/System.Windows.Forms.Primitives.csproj
+++ b/src/System.Windows.Forms.Primitives/src/System.Windows.Forms.Primitives.csproj
@@ -15,8 +15,9 @@
     <NoWarn>$(NoWarn);CS8981;CS3016</NoWarn>
     <!--
       We don't care about CLS compliance since everything here is internal and we want to match native types.
+      CS3019: CsWin32-generated COM structs carry [CLSCompliant] attributes on internal (non-visible) types.
     -->
-    <NoWarn>$(NoWarn);CS3016</NoWarn>
+    <NoWarn>$(NoWarn);CS3016;CS3019</NoWarn>
     <!--
       IL Trim warnings which should be removed in order to make WinForms trimmable
       See https://github.com/dotnet/winforms/issues/4649
diff --git a/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.GetThemeDocumentationProperty.cs b/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.GetThemeDocumentationProperty.cs
index a5402c364f6..9105054555a 100644
--- a/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.GetThemeDocumentationProperty.cs
+++ b/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.GetThemeDocumentationProperty.cs
@@ -9,8 +9,10 @@ public static unsafe string GetThemeDocumentationProperty(string pszThemeName, s
     {
         Span<char> buffer = stackalloc char[512];
         fixed (char* pBuffer = buffer)
+        fixed (char* pszTheme = pszThemeName)
+        fixed (char* pszProperty = pszPropertyName)
         {
-            GetThemeDocumentationProperty(pszThemeName, pszPropertyName, pBuffer, buffer.Length);
+            GetThemeDocumentationProperty(pszTheme, pszProperty, pBuffer, buffer.Length);
         }
 
         return buffer.SliceAtFirstNull().ToString();
diff --git a/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.SHCreateShellItem.cs b/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.SHCreateShellItem.cs
index ccc0f9ce039..bdfed58648e 100644
--- a/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.SHCreateShellItem.cs
+++ b/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.SHCreateShellItem.cs
@@ -9,7 +9,7 @@ internal static partial class PInvoke
     public static unsafe IShellItem* SHCreateShellItem(string path)
     {
         IShellItem* ppsi = default;
-        if (SHParseDisplayName(path, pbc: null, out ITEMIDLIST* ppidl, sfgaoIn: 0, psfgaoOut: null).Succeeded)
+        if (SHParseDisplayName(path, pbc: null, out ITEMIDLIST* ppidl, sfgaoIn: 0).Succeeded)
         {
             // No parent specified
             SHCreateShellItem(pidlParent: null, psfParent: null, ppidl, &ppsi);
diff --git a/src/System.Windows.Forms.Primitives/src/Windows/Win32/Pinvoke.RegLoadMUIString.cs b/src/System.Windows.Forms.Primitives/src/Windows/Win32/Pinvoke.RegLoadMUIString.cs
index 96ab275ebf8..e9962430b1b 100644
--- a/src/System.Windows.Forms.Primitives/src/Windows/Win32/Pinvoke.RegLoadMUIString.cs
+++ b/src/System.Windows.Forms.Primitives/src/Windows/Win32/Pinvoke.RegLoadMUIString.cs
@@ -8,7 +8,7 @@ namespace Windows.Win32;
 
 internal static partial class PInvoke
 {
-    /// <inheritdoc cref="RegLoadMUIString(System.Registry.HKEY, string, PWSTR, uint, uint*, uint, string)"/>
+    /// <inheritdoc cref="RegLoadMUIString(System.Registry.HKEY, PCWSTR, PWSTR, uint, uint*, uint, PCWSTR)"/>
     [SkipLocalsInit]
     public static unsafe bool RegLoadMUIString(RegistryKey key, string keyName, out string localizedValue)
     {
@@ -17,11 +17,12 @@ public static unsafe bool RegLoadMUIString(RegistryKey key, string keyName, out
         while (true)
         {
             fixed (char* pszOutBuf = buffer)
+            fixed (char* pszKeyName = keyName)
             {
                 uint bytes = 0;
                 var errorCode = RegLoadMUIString(
                     (System.Registry.HKEY)key.Handle.DangerousGetHandle(),
-                    keyName,
+                    pszKeyName,
                     pszOutBuf,
                     (uint)(buffer.Length * sizeof(char)),
                     &bytes,
diff --git a/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Shell32/ShellItemTests.cs b/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Shell32/ShellItemTests.cs
index b928c0d1c86..2cbffb0060b 100644
--- a/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Shell32/ShellItemTests.cs
+++ b/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Shell32/ShellItemTests.cs
@@ -12,8 +12,7 @@ public class ShellItemTests
     public unsafe void SHParseDisplayName_ValidPath()
     {
         string path = Path.GetTempPath();
-        uint rgflnOut = default;
-        HRESULT result = PInvoke.SHParseDisplayName(path, pbc: null, out ITEMIDLIST* ppidl, 0, &rgflnOut);
+        HRESULT result = PInvoke.SHParseDisplayName(path, pbc: null, out ITEMIDLIST* ppidl, 0);
         try
         {
             Assert.Equal(HRESULT.S_OK, result);
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Accessibility/AccessibleObjectExtensions.cs b/src/System.Windows.Forms/System/Windows/Forms/Accessibility/AccessibleObjectExtensions.cs
index 038448fb648..27023e34d8f 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Accessibility/AccessibleObjectExtensions.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Accessibility/AccessibleObjectExtensions.cs
@@ -264,7 +264,7 @@ public static (int topic, BSTR helpFile) TryGetHelpTopic(this AgileComPointer<IA
         }
 
         BSTR file = default;
-        result = accessible.Value->get_accHelpTopic(&file, child, out int topicId);
+        result = accessible.Value->get_accHelpTopic(out file, child, out int topicId);
         Debug.Assert(
             result.Succeeded || result == HRESULT.DISP_E_MEMBERNOTFOUND,
             $"{nameof(TryGetHelpTopic)}: put_accValue call failed with {result}");
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/ButtonInternal/CheckBoxBaseAdapter.cs b/src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/ButtonInternal/CheckBoxBaseAdapter.cs
index ae30fc150b6..2192caa1598 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/ButtonInternal/CheckBoxBaseAdapter.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/ButtonInternal/CheckBoxBaseAdapter.cs
@@ -314,8 +314,8 @@ private static Bitmap GetCheckBoxImage(Color checkColor, Rectangle fullSize, ref
             PInvoke.DrawFrameControl(
                 hdc,
                 ref rcCheck,
-                DFC_TYPE.DFC_MENU,
-                DFCS_STATE.DFCS_MENUCHECK);
+                (uint)DFC_TYPE.DFC_MENU,
+                (uint)DFCS_STATE.DFCS_MENUCHECK);
         }
 
         bitmap.MakeTransparent();
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Controls/DataGridView/DataGridViewCheckBoxCell.cs b/src/System.Windows.Forms/System/Windows/Forms/Controls/DataGridView/DataGridViewCheckBoxCell.cs
index eeeaac207eb..c16bbeace51 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Controls/DataGridView/DataGridViewCheckBoxCell.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Controls/DataGridView/DataGridViewCheckBoxCell.cs
@@ -1361,8 +1361,8 @@ private Rectangle PaintPrivate(
                                     PInvoke.DrawFrameControl(
                                         hdc,
                                         ref rcCheck,
-                                        DFC_TYPE.DFC_MENU,
-                                        DFCS_STATE.DFCS_MENUCHECK);
+                                        (uint)DFC_TYPE.DFC_MENU,
+                                        (uint)DFCS_STATE.DFCS_MENUCHECK);
                                 }
 
                                 bitmap.MakeTransparent();
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Help/Help.cs b/src/System.Windows.Forms/System/Windows/Forms/Help/Help.cs
index 445bf395138..3118f7dc382 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Help/Help.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Help/Help.cs
@@ -119,16 +119,16 @@ private static unsafe void ShowHTML10Help(Control? parent, string? url, HelpNavi
         {
             string? localPath = (file is not null && file.IsFile) ? file.LocalPath : url;
 
-            // If this is a local path, convert it to a short path name. Pass 0 as the length the first time
-            uint requiredStringSize = PInvoke.GetShortPathName(localPath, null, 0);
-            if (requiredStringSize > 0)
+            // If this is a local path, convert it to a short path name. Pass an empty buffer the first time to get the size.
+            if (localPath is not null)
             {
-                // It's able to make it a short path.
-                using BufferScope<char> shortName = new((int)requiredStringSize);
-                fixed (char* pShortName = shortName)
+                uint requiredStringSize = PInvoke.GetShortPathName(localPath, default);
+                if (requiredStringSize > 0)
                 {
-                    requiredStringSize = PInvoke.GetShortPathName(localPath, pShortName, requiredStringSize);
-                    // If it can't make it a  short path, just leave the path we had.
+                    // It's able to make it a short path.
+                    using BufferScope<char> shortName = new((int)requiredStringSize);
+                    requiredStringSize = PInvoke.GetShortPathName(localPath, shortName);
+                    // If it can't make it a short path, just leave the path we had.
                     pathAndFileName = shortName[..(int)requiredStringSize].ToString();
                 }
             }
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Printing/PageSetupDialog.cs b/src/System.Windows.Forms/System/Windows/Forms/Printing/PageSetupDialog.cs
index 6853b30f318..53737bcaef8 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Printing/PageSetupDialog.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Printing/PageSetupDialog.cs
@@ -285,9 +285,10 @@ protected override unsafe bool RunDialog(IntPtr hwndOwner)
             Span<char> buffer = stackalloc char[2];
             int result;
             fixed (char* pBuffer = buffer)
+            fixed (char* pLocaleName = PInvoke.LOCALE_NAME_SYSTEM_DEFAULT)
             {
                 result = PInvoke.GetLocaleInfoEx(
-                    PInvoke.LOCALE_NAME_SYSTEM_DEFAULT,
+                    pLocaleName,
                     PInvoke.LOCALE_IMEASURE,
                     pBuffer,
                     buffer.Length);
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Printing/PrinterSettingsExtensions.cs b/src/System.Windows.Forms/System/Windows/Forms/Printing/PrinterSettingsExtensions.cs
index 97da16920f6..06d6b5a954e 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Printing/PrinterSettingsExtensions.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Printing/PrinterSettingsExtensions.cs
@@ -23,7 +23,7 @@ internal static unsafe DevModeScope GetDevMode(PrinterSettings printerSettings)
 
         fixed (char* n = printerSettings.PrinterName)
         {
-            modeSize = PInvoke.DocumentProperties(HWND.Null, HANDLE.Null, n, null, (DEVMODEW*)null, 0);
+            modeSize = PInvoke.DocumentProperties(HWND.Null, global::Windows.Win32.Graphics.Printing.PRINTER_HANDLE.Null, n, null, (DEVMODEW*)null, 0);
             if (modeSize < 1)
             {
                 throw new InvalidPrinterException(printerSettings);
@@ -37,7 +37,7 @@ internal static unsafe DevModeScope GetDevMode(PrinterSettings printerSettings)
         {
             modeSize = PInvoke.DocumentProperties(
                 HWND.Null,
-                HANDLE.Null,
+                global::Windows.Win32.Graphics.Printing.PRINTER_HANDLE.Null,
                 n,
                 (DEVMODEW*)b,
                 (DEVMODEW*)null,
diff --git a/src/System.Windows.Forms/System/Windows/Forms/Rendering/ControlPaint.cs b/src/System.Windows.Forms/System/Windows/Forms/Rendering/ControlPaint.cs
index 61ec35d8936..debb4fc6ac3 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/Rendering/ControlPaint.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/Rendering/ControlPaint.cs
@@ -1401,7 +1401,7 @@ private static void DrawFlatCheckBox(
                 {
                     g2.Clear(Color.Transparent);
                     using DeviceContextHdcScope dc = new(g2, applyGraphicsState: false);
-                    PInvoke.DrawFrameControl(dc, ref rcCheck, DFC_TYPE.DFC_MENU, DFCS_STATE.DFCS_MENUCHECK);
+                    PInvoke.DrawFrameControl(dc, ref rcCheck, (uint)DFC_TYPE.DFC_MENU, (uint)DFCS_STATE.DFCS_MENUCHECK);
                 }
 
                 bitmap.MakeTransparent();
@@ -1473,7 +1473,7 @@ private static void DrawFrameControl(
         using (DeviceContextHdcScope hdc = new(g2, applyGraphicsState: false))
         {
             // Get Win32 dc with Graphics properties applied to it.
-            PInvoke.DrawFrameControl(hdc, ref rcFrame, kind, state);
+            PInvoke.DrawFrameControl(hdc, ref rcFrame, (uint)kind, (uint)state);
         }
 
         if (foreColor == Color.Empty || backColor == Color.Empty)
diff --git a/src/System.Windows.Forms/System/Windows/Forms/VisualStyles/VisualStyleRenderer.cs b/src/System.Windows.Forms/System/Windows/Forms/VisualStyles/VisualStyleRenderer.cs
index 0193aacf849..b2a0189cd73 100644
--- a/src/System.Windows.Forms/System/Windows/Forms/VisualStyles/VisualStyleRenderer.cs
+++ b/src/System.Windows.Forms/System/Windows/Forms/VisualStyles/VisualStyleRenderer.cs
@@ -287,7 +287,7 @@ internal unsafe Rectangle DrawEdge(HDC dc, Rectangle bounds, Edges edges, EdgeSt
             bounds,
             (DRAWEDGE_FLAGS)style,
             (DRAW_EDGE_FLAGS)edges | (DRAW_EDGE_FLAGS)effects | DRAW_EDGE_FLAGS.BF_ADJUST,
-            &contentRect);
+            out contentRect);
 
         return contentRect;
     }
@@ -454,7 +454,7 @@ public Rectangle GetBackgroundExtent(IDeviceContext dc, Rectangle contentBounds)
 
         using DeviceContextHdcScope hdc = dc.ToHdcScope();
         HRGN hrgn;
-        _lastHResult = PInvoke.GetThemeBackgroundRegion(HTHEME, hdc, Part, State, bounds, &hrgn);
+        _lastHResult = PInvoke.GetThemeBackgroundRegion(HTHEME, hdc, Part, State, bounds, out hrgn);
 
         // GetThemeBackgroundRegion returns a null hRegion if it fails to create one, it could be because the bounding
         // box is too big. For more info see code in %xpsrc%\shell\themes\uxtheme\imagefile.cpp if you have an enlistment to it.