diff --git a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Benchmark/HowToValidateGuidBenchmark.cs b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Benchmark/HowToValidateGuidBenchmark.cs
index 46455e3d2e..a1eae8bb2a 100644
--- a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Benchmark/HowToValidateGuidBenchmark.cs
+++ b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Benchmark/HowToValidateGuidBenchmark.cs
@@ -4,7 +4,7 @@
 using BenchmarkDotNet.Order;
 using HowToValidateGuid;
 
-namespace HowToUseStringPool.Benchmark;
+namespace HowToValidateGuid.Benchmark;
 
 [Orderer(SummaryOrderPolicy.FastestToSlowest)]
 [GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByParams)]
diff --git a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/GuidHelper.cs b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/GuidHelper.cs
index dc8dc38f6e..9769cef395 100644
--- a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/GuidHelper.cs
+++ b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/GuidHelper.cs
@@ -7,18 +7,18 @@ public partial class GuidHelper
     [GeneratedRegex("^[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{12}$")]
     private static partial Regex GuidValidatorRegex();
 
-    public static bool ValidateWithRegex(string input)
+    public static bool ValidateWithRegex(string? input)
     {
-        return GuidValidatorRegex().IsMatch(input);
+        return input is not null && GuidValidatorRegex().IsMatch(input);
     }
 
-    public static bool ValidateWithGuidParse(string input)
+    public static bool ValidateWithGuidParse(string? input)
     {
         try
         {
-            Guid.Parse(input);
+            Guid.Parse(input!);
         }
-        catch (FormatException)
+        catch (Exception ex) when (ex is FormatException or ArgumentNullException)
         {
             return false;
         }
@@ -26,13 +26,13 @@ public static bool ValidateWithGuidParse(string input)
         return true;
     }
 
-    public static bool ValidateWithGuidParseExact(string input, string format)
+    public static bool ValidateWithGuidParseExact(string? input, string format)
     {
         try
         {
-            Guid.ParseExact(input, format);
+            Guid.ParseExact(input!, format);
         }
-        catch (FormatException)
+        catch (Exception ex) when (ex is FormatException or ArgumentNullException)
         {
             return false;
         }
@@ -40,27 +40,30 @@ public static bool ValidateWithGuidParseExact(string input, string format)
         return true;
     }
 
-    public static bool ValidateWithGuidTryParse(string input)
+    public static bool ValidateWithGuidTryParse(string? input)
     {
         return Guid.TryParse(input, out Guid _);
     }
 
-    public static bool ValidateWithGuidTryParseExact(string input, string format)
+    public static bool ValidateWithGuidTryParseExact(string? input, string format)
     {
         return Guid.TryParseExact(input, format, out Guid _);
     }
 
-    public static bool ValidateWithNewGuid(string input)
+    public static bool ValidateWithNewGuid(string? input)
     {
         try
         {
-            var _ = new Guid(input);
+            var _ = new Guid(input!);
         }
-        catch (FormatException)
+        catch (Exception ex) when (ex is FormatException or ArgumentNullException)
         {
             return false;
         }
 
         return true;
     }
+
+    public static bool IsUsableGuid(string? input) =>
+        Guid.TryParse(input, out var id) && id != Guid.Empty;
 }
diff --git a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/HowToValidateGuid.csproj b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/HowToValidateGuid.csproj
index 2b8181b980..c96a8eb1e7 100644
--- a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/HowToValidateGuid.csproj
+++ b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/HowToValidateGuid.csproj
@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>disable</Nullable>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.12" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
   </ItemGroup>
 
 </Project>
diff --git a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Program.cs b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Program.cs
index 1c19c874ac..7b59902989 100644
--- a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Program.cs
+++ b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuid/Program.cs
@@ -1,5 +1,5 @@
 using BenchmarkDotNet.Running;
-using HowToUseStringPool.Benchmark;
+using HowToValidateGuid.Benchmark;
 using HowToValidateGuid;
 
 BenchmarkRunner.Run<HowToValidateGuidBenchmark>();
diff --git a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/GuidHelperTests.cs b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/GuidHelperTests.cs
index 85b036f5b7..186221e43f 100644
--- a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/GuidHelperTests.cs
+++ b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/GuidHelperTests.cs
@@ -6,7 +6,7 @@ namespace HowToValidateGuidTests
     [TestClass]
     public class GuidHelperTests
     {
-        private IFixture _fixture;
+        private IFixture _fixture = new Fixture();
         private const string formatKey = "D";
 
         [TestInitialize]
@@ -41,6 +41,14 @@ public void WhenValidateWithRegexCalled_ForAEmptyString_ThenResultMustBeFalse()
             Validate(input, GuidHelper.ValidateWithRegex, false);
         }
 
+        [TestMethod]
+        public void WhenValidateWithRegexCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            Validate(input, GuidHelper.ValidateWithRegex, false);
+        }
+
         #endregion
 
         #region ValidateWithGuidParse
@@ -69,6 +77,14 @@ public void WhenValidateWithGuidParseCalled_ForAEmptyString_ThenResultMustBeFals
             Validate(input, GuidHelper.ValidateWithGuidParse, false);
         }
 
+        [TestMethod]
+        public void WhenValidateWithGuidParseCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            Validate(input, GuidHelper.ValidateWithGuidParse, false);
+        }
+
         #endregion
 
         #region ValidateWithGuidParseExact
@@ -97,6 +113,22 @@ public void WhenValidateWithGuidParseExactCalled_ForAEmptyString_ThenResultMustB
             ValidateFormat(input, formatKey, GuidHelper.ValidateWithGuidParseExact, false);
         }
 
+        [TestMethod]
+        public void WhenValidateWithGuidParseExactCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            ValidateFormat(input, formatKey, GuidHelper.ValidateWithGuidParseExact, false);
+        }
+
+        [TestMethod]
+        public void WhenValidateWithGuidParseExactCalled_ForAGuidStringInXFormat_ThenResultMustBeTrue()
+        {
+            var input = _fixture.Create<Guid>().ToString("X");
+
+            ValidateFormat(input, "X", GuidHelper.ValidateWithGuidParseExact, true);
+        }
+
         #endregion
 
         #region ValidateWithGuidTryParse
@@ -125,6 +157,14 @@ public void WhenValidateWithGuidTryParseCalled_ForAEmptyString_ThenResultMustBeF
             Validate(input, GuidHelper.ValidateWithGuidTryParse, false);
         }
 
+        [TestMethod]
+        public void WhenValidateWithGuidTryParseCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            Validate(input, GuidHelper.ValidateWithGuidTryParse, false);
+        }
+
         #endregion
 
         #region ValidateWithGuidTryParseExact
@@ -153,6 +193,22 @@ public void WhenValidateWithGuidTryParseExactCalled_ForAEmptyString_ThenResultMu
             ValidateFormat(input, formatKey, GuidHelper.ValidateWithGuidTryParseExact, false);
         }
 
+        [TestMethod]
+        public void WhenValidateWithGuidTryParseExactCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            ValidateFormat(input, formatKey, GuidHelper.ValidateWithGuidTryParseExact, false);
+        }
+
+        [TestMethod]
+        public void WhenValidateWithGuidTryParseExactCalled_ForAGuidStringInXFormat_ThenResultMustBeTrue()
+        {
+            var input = _fixture.Create<Guid>().ToString("X");
+
+            ValidateFormat(input, "X", GuidHelper.ValidateWithGuidTryParseExact, true);
+        }
+
         #endregion
 
         #region ValidateWithNewGuid
@@ -181,16 +237,60 @@ public void WhenValidateWithNewGuidCalled_ForAEmptyString_ThenResultMustBeFalse(
             Validate(input, GuidHelper.ValidateWithNewGuid, false);
         }
 
+        [TestMethod]
+        public void WhenValidateWithNewGuidCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            Validate(input, GuidHelper.ValidateWithNewGuid, false);
+        }
+
+        #endregion
+
+        #region IsUsableGuid
+
+        [TestMethod]
+        public void WhenIsUsableGuidCalled_ForANullString_ThenResultMustBeFalse()
+        {
+            string? input = null;
+
+            Validate(input, GuidHelper.IsUsableGuid, false);
+        }
+
+        [TestMethod]
+        public void WhenIsUsableGuidCalled_ForARandomString_ThenResultMustBeFalse()
+        {
+            var input = _fixture.Create<string>() + _fixture.Create<string>();
+
+            Validate(input, GuidHelper.IsUsableGuid, false);
+        }
+
+        [TestMethod]
+        public void WhenIsUsableGuidCalled_ForAnEmptyGuidString_ThenResultMustBeFalse()
+        {
+            var input = Guid.Empty.ToString();
+
+            Validate(input, GuidHelper.IsUsableGuid, false);
+        }
+
+        [TestMethod]
+        public void WhenIsUsableGuidCalled_ForAGuidString_ThenResultMustBeTrue()
+        {
+            var input = _fixture.Create<Guid>().ToString();
+
+            Validate(input, GuidHelper.IsUsableGuid, true);
+        }
+
         #endregion
 
-        private void Validate(string input, Func<string, bool> action, bool expected)
+        private void Validate(string? input, Func<string?, bool> action, bool expected)
         {
             var result = action(input);
 
             Assert.AreEqual(expected, result);
         }
 
-        private void ValidateFormat(string input, string format, Func<string, string, bool> action, bool expected)
+        private void ValidateFormat(string? input, string format, Func<string?, string, bool> action, bool expected)
         {
             var result = action(input, format);
 
diff --git a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/HowToValidateGuidTests.csproj b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/HowToValidateGuidTests.csproj
index ef9dbc677a..2c39eee1fe 100644
--- a/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/HowToValidateGuidTests.csproj
+++ b/csharp-classes-struct-record/HowToValidateGuid/HowToValidateGuidTests/HowToValidateGuidTests.csproj
@@ -1,20 +1,20 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>disable</Nullable>
+    <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="3.0.4" />
-    <PackageReference Include="MSTest.TestFramework" Version="3.0.4" />
-    <PackageReference Include="coverlet.collector" Version="6.0.0" />
-    <PackageReference Include="AutoFixture" Version="4.18.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="4.5.1" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.5.1" />
+    <PackageReference Include="coverlet.collector" Version="10.1.0" />
+    <PackageReference Include="AutoFixture" Version="4.18.1" />
   </ItemGroup>
 
   <ItemGroup>