diff --git a/src/Foundry.Connect.Tests/NativeWifiApiTests.cs b/src/Foundry.Connect.Tests/NativeWifiApiTests.cs
new file mode 100644
index 000000000..8e3ce4e9e
--- /dev/null
+++ b/src/Foundry.Connect.Tests/NativeWifiApiTests.cs
@@ -0,0 +1,27 @@
+// Copyright (c) Foundry Project contributors.
+// Licensed under the MIT License.
+// See the LICENSE file in the project root for more information.
+
+using System.Reflection;
+using Foundry.Connect.Services.Network;
+
+namespace Foundry.Connect.Tests;
+
+public sealed class NativeWifiApiTests
+{
+    // wlanapi takes interface identifiers as const GUID*. A by-value Guid only reaches the callee as a
+    // pointer under the x64 calling convention; ARM64 passes it in two registers and every call fails.
+    [Fact]
+    public void WlanImports_PassInterfaceGuidsByReference()
+    {
+        MethodInfo[] imports = typeof(NativeWifiApi)
+            .GetMethods(BindingFlags.Static | BindingFlags.NonPublic)
+            .Where(static method => method.Attributes.HasFlag(MethodAttributes.PinvokeImpl))
+            .ToArray();
+
+        Assert.NotEmpty(imports);
+        Assert.DoesNotContain(
+            imports.SelectMany(static method => method.GetParameters()),
+            static parameter => parameter.ParameterType == typeof(Guid));
+    }
+}
diff --git a/src/Foundry.Connect/Services/Network/NativeWifiApi.cs b/src/Foundry.Connect/Services/Network/NativeWifiApi.cs
index 68bfa692c..09382d78f 100644
--- a/src/Foundry.Connect/Services/Network/NativeWifiApi.cs
+++ b/src/Foundry.Connect/Services/Network/NativeWifiApi.cs
@@ -12,6 +12,11 @@ namespace Foundry.Connect.Services.Network;
 /// <summary>
 /// Provides the native WLAN API calls used by Foundry.Connect to discover and inspect Wi-Fi state.
 /// </summary>
+/// <remarks>
+/// Interface identifiers must be declared as <see langword="in"/> <see cref="Guid"/> because wlanapi expects
+/// <c>const GUID*</c>. A by-value <see cref="Guid"/> only works on x64, where the calling convention happens to
+/// pass 16-byte structures by reference; ARM64 passes them in registers and the calls fail.
+/// </remarks>
 internal static class NativeWifiApi
 {
     private const uint ClientVersion = 2;
@@ -404,7 +409,7 @@ private static extern uint WlanEnumInterfaces(
     [DllImport("wlanapi.dll")]
     private static extern uint WlanGetAvailableNetworkList(
         IntPtr clientHandle,
-        Guid interfaceGuid,
+        in Guid interfaceGuid,
         uint flags,
         IntPtr reserved,
         out IntPtr availableNetworkList);
@@ -412,7 +417,7 @@ private static extern uint WlanGetAvailableNetworkList(
     [DllImport("wlanapi.dll")]
     private static extern uint WlanScan(
         IntPtr clientHandle,
-        Guid interfaceGuid,
+        in Guid interfaceGuid,
         IntPtr dot11Ssid,
         IntPtr ieData,
         IntPtr reserved);
@@ -420,7 +425,7 @@ private static extern uint WlanScan(
     [DllImport("wlanapi.dll")]
     private static extern uint WlanQueryInterface(
         IntPtr clientHandle,
-        Guid interfaceGuid,
+        in Guid interfaceGuid,
         WlanIntfOpcode opCode,
         IntPtr reserved,
         out uint dataSize,