diff --git a/src/ElectronNET.IntegrationTests/Tests/MigrationChecksTargetsTests.cs b/src/ElectronNET.IntegrationTests/Tests/MigrationChecksTargetsTests.cs
new file mode 100644
index 00000000..93b18173
--- /dev/null
+++ b/src/ElectronNET.IntegrationTests/Tests/MigrationChecksTargetsTests.cs
@@ -0,0 +1,193 @@
+using System.Diagnostics;
+
+namespace ElectronNET.IntegrationTests.Tests;
+
+/// <summary>
+/// Unit tests for ElectronNET.MigrationChecks.targets - no Electron runtime required.
+/// Covers GitHub issue #1035: System.IO.File.ReadAllLines is not available as an MSBuild
+/// property function on all platforms (e.g. macOS GitHub Actions), causing MSB4185.
+/// </summary>
+public class MigrationChecksTargetsTests
+{
+    private static readonly string TargetsFilePath = FindTargetsFile();
+
+    /// <summary>
+    /// Walks up the directory tree from <see cref="AppContext.BaseDirectory"/> until it finds
+    /// the migration checks targets file. This is robust against varying output paths
+    /// (with or without RID subfolder, debug/release, etc.).
+    /// </summary>
+    private static string FindTargetsFile()
+    {
+        const string RelativeFromRepoRoot =
+            "src/ElectronNET/build/ElectronNET.MigrationChecks.targets";
+        const string RelativeFromSrc =
+            "ElectronNET/build/ElectronNET.MigrationChecks.targets";
+
+        var dir = new DirectoryInfo(AppContext.BaseDirectory);
+        while (dir != null)
+        {
+            var fromRepoRoot = Path.Combine(dir.FullName, RelativeFromRepoRoot);
+            if (File.Exists(fromRepoRoot))
+            {
+                return Path.GetFullPath(fromRepoRoot);
+            }
+
+            var fromSrc = Path.Combine(dir.FullName, RelativeFromSrc);
+            if (File.Exists(fromSrc))
+            {
+                return Path.GetFullPath(fromSrc);
+            }
+
+            dir = dir.Parent;
+        }
+
+        throw new FileNotFoundException(
+            "Could not locate ElectronNET.MigrationChecks.targets by walking up from " +
+            $"'{AppContext.BaseDirectory}'.");
+    }
+
+    // -----------------------------------------------------------------------
+    // Content-level test (RED before fix, GREEN after fix on ALL platforms)
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void MigrationChecksTargets_ShouldNotUseReadAllLines()
+    {
+        // The file must exist - if this fails the path constant above is wrong.
+        File.Exists(TargetsFilePath).Should().BeTrue(
+            $"targets file must exist at '{TargetsFilePath}'");
+
+        var content = File.ReadAllText(TargetsFilePath);
+
+        // System.IO.File::ReadAllLines is not in the MSBuild property-function
+        // whitelist on all platforms (MSB4185 on macOS GitHub Actions, see #1035).
+        // ReadAllText must be used instead.
+        content.Should().NotContain(
+            "::ReadAllLines(",
+            "because ReadAllLines is not available as an MSBuild property function on all " +
+            "platforms. Use ReadAllText instead (GitHub issue #1035).");
+    }
+
+    // -----------------------------------------------------------------------
+    // Functional build test - verifies no MSB4185 at runtime
+    // (RED on platforms where ReadAllLines is restricted, GREEN after fix)
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public async Task MigrationChecksTargets_BuildWithCleanPackageJson_ShouldSucceedWithoutMSB4185()
+    {
+        // Positive case: a package.json that does NOT mention electron.
+        // The migration check must successfully read the file via ReadAllText
+        // (the code path fixed by issue #1035) without producing MSB4185.
+
+        var tempDir = CreateTempProjectDirectory();
+        try
+        {
+            await File.WriteAllTextAsync(
+                Path.Combine(tempDir, "package.json"),
+                """{ "devDependencies": { "vite": "^5.0.0" } }""");
+
+            await WriteMinimalCsprojAsync(tempDir);
+
+            var (exitCode, output) = await RunDotnetBuildAsync(tempDir);
+
+            exitCode.Should().Be(0,
+                $"the build must succeed when the package.json contains no electron references. " +
+                $"Full build output:\n{output}");
+
+            output.Should().NotContain(
+                "MSB4185",
+                $"ReadAllLines must not be used as an MSBuild property function. " +
+                $"Full build output:\n{output}");
+        }
+        finally
+        {
+            Directory.Delete(tempDir, recursive: true);
+        }
+    }
+
+    [Fact]
+    public async Task MigrationChecksTargets_BuildWithPackageJsonContainingElectron_ShouldEmitELECTRON008WarningWithoutMSB4185()
+    {
+        // Negative case: a package.json that DOES contain "electron".
+        // The migration check must still read the file successfully (no MSB4185)
+        // and must emit the expected ELECTRON008 warning. ELECTRON008 is a
+        // <Warning>, not an <Error>, so the build itself still succeeds.
+
+        var tempDir = CreateTempProjectDirectory();
+        try
+        {
+            await File.WriteAllTextAsync(
+                Path.Combine(tempDir, "package.json"),
+                """{ "devDependencies": { "electron": "^30.0.0" } }""");
+
+            await WriteMinimalCsprojAsync(tempDir);
+
+            var (exitCode, output) = await RunDotnetBuildAsync(tempDir);
+
+            exitCode.Should().Be(0,
+                $"ELECTRON008 is a Warning (not an Error) so the build itself must still " +
+                $"succeed. Full build output:\n{output}");
+
+            output.Should().NotContain(
+                "MSB4185",
+                $"ReadAllLines must not be used as an MSBuild property function. " +
+                $"Full build output:\n{output}");
+
+            output.Should().Contain(
+                "ELECTRON008",
+                $"the migration check must still detect electron references in package.json " +
+                $"after the ReadAllText migration. Full build output:\n{output}");
+        }
+        finally
+        {
+            Directory.Delete(tempDir, recursive: true);
+        }
+    }
+
+    // -----------------------------------------------------------------------
+    // Helpers
+    // -----------------------------------------------------------------------
+
+    private static string CreateTempProjectDirectory()
+    {
+        var tempDir = Path.Combine(Path.GetTempPath(), $"electron-net-test-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(tempDir);
+        return tempDir;
+    }
+
+    private static Task WriteMinimalCsprojAsync(string tempDir)
+    {
+        // A minimal csproj that only imports the migration checks targets to keep the
+        // build fast. Note: MSBuildProjectDirectory is a reserved MSBuild property and
+        // must not be redefined manually; MSBuild sets it automatically to the folder
+        // of the csproj (which is tempDir here).
+        var targetsPathEscaped = TargetsFilePath.Replace("'", "&apos;");
+        return File.WriteAllTextAsync(
+            Path.Combine(tempDir, "TestApp.csproj"),
+            $"""
+            <Project>
+              <Import Project="{targetsPathEscaped}" />
+              <Target Name="Build" DependsOnTargets="ElectronMigrationChecks" />
+            </Project>
+            """);
+    }
+
+    private static async Task<(int ExitCode, string Output)> RunDotnetBuildAsync(string workingDirectory)
+    {
+        var psi = new ProcessStartInfo("dotnet", "build --nologo -v:minimal")
+        {
+            WorkingDirectory = workingDirectory,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false,
+        };
+
+        using var process = Process.Start(psi)!;
+        var stdOut = await process.StandardOutput.ReadToEndAsync();
+        var stdErr = await process.StandardError.ReadToEndAsync();
+        await process.WaitForExitAsync();
+
+        return (process.ExitCode, stdOut + stdErr);
+    }
+}
diff --git a/src/ElectronNET/build/ElectronNET.MigrationChecks.targets b/src/ElectronNET/build/ElectronNET.MigrationChecks.targets
index 666c1785..ab138a5d 100644
--- a/src/ElectronNET/build/ElectronNET.MigrationChecks.targets
+++ b/src/ElectronNET/build/ElectronNET.MigrationChecks.targets
@@ -73,12 +73,11 @@ EXCEPTION:
   <Target Name="ElectronCheckRootPackageJsonNoElectron"
           Condition="Exists('$(MSBuildProjectDirectory)\package.json')">
 
-    <ItemGroup>
-      <_RootPackageJsonLines Include="$([System.IO.File]::ReadAllLines('$(MSBuildProjectDirectory)\package.json'))" />
-    </ItemGroup>
-
     <PropertyGroup>
-      <_RootPackageJsonContent>@(_RootPackageJsonLines, ' ')</_RootPackageJsonContent>
+      <!-- ReadAllText is used here instead of ReadAllLines because ReadAllLines is not available
+           as an MSBuild property function on all platforms (e.g. macOS GitHub Actions), which
+           caused MSB4185. ReadAllText is universally supported. See GitHub issue #1035. -->
+      <_RootPackageJsonContent>$([System.IO.File]::ReadAllText('$(MSBuildProjectDirectory)\package.json'))</_RootPackageJsonContent>
       <_RootPackageJsonHasElectron>false</_RootPackageJsonHasElectron>
       <_RootPackageJsonHasElectron Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('$(_RootPackageJsonContent)', 'electron', System.Text.RegularExpressions.RegexOptions.IgnoreCase))">true</_RootPackageJsonHasElectron>
     </PropertyGroup>