diff --git a/LibGit2Sharp.Tests/CommitFixture.cs b/LibGit2Sharp.Tests/CommitFixture.cs
index 6ac64c31f..a4d7eca44 100644
--- a/LibGit2Sharp.Tests/CommitFixture.cs
+++ b/LibGit2Sharp.Tests/CommitFixture.cs
@@ -5,6 +5,7 @@
 using LibGit2Sharp.Core;
 using LibGit2Sharp.Tests.TestHelpers;
 using Xunit;
+using Xunit.Extensions;
 
 namespace LibGit2Sharp.Tests
 {
@@ -519,6 +520,27 @@ public void DirectlyAccessingAnUnknownTreeEntryOfTheCommitReturnsNull()
             }
         }
 
+        [Theory]
+        [InlineData(null, "x@example.com")]
+        [InlineData("", "x@example.com")]
+        [InlineData("X", null)]
+        [InlineData("X", "")]
+        public void CommitWithInvalidSignatureConfigThrows(string name, string email)
+        {
+            string repoPath = InitNewRepository();
+            string configPath = CreateConfigurationWithDummyUser(name, email);
+            var options = new RepositoryOptions { GlobalConfigurationLocation = configPath };
+
+            using (var repo = new Repository(repoPath, options))
+            {
+                Assert.Equal(name, repo.Config.GetValueOrDefault<string>("user.name"));
+                Assert.Equal(email, repo.Config.GetValueOrDefault<string>("user.email"));
+
+                Assert.Throws<LibGit2SharpException>(
+                    () => repo.Commit("Initial egotistic commit", new CommitOptions { AllowEmptyCommit = true }));
+            }
+        }
+
         [Fact]
         public void CanCommitWithSignatureFromConfig()
         {
diff --git a/LibGit2Sharp.Tests/SignatureFixture.cs b/LibGit2Sharp.Tests/SignatureFixture.cs
index 978141837..e40cabd6c 100644
--- a/LibGit2Sharp.Tests/SignatureFixture.cs
+++ b/LibGit2Sharp.Tests/SignatureFixture.cs
@@ -35,13 +35,7 @@ public void CreatingASignatureWithBadParamsThrows()
             Assert.Throws<ArgumentNullException>(() => new Signature(null, "me@there.com", DateTimeOffset.Now));
             Assert.Throws<ArgumentException>(() => new Signature(string.Empty, "me@there.com", DateTimeOffset.Now));
             Assert.Throws<ArgumentNullException>(() => new Signature("Me", null, DateTimeOffset.Now));
-        }
-
-        [Fact]
-        public void CanCreateASignatureWithAnEmptyEmail()
-        {
-            var sig = new Signature("Me", string.Empty, DateTimeOffset.Now);
-            Assert.Equal(string.Empty, sig.Email);
+            Assert.Throws<ArgumentException>(() => new Signature("Me", string.Empty, DateTimeOffset.Now));
         }
     }
 }
diff --git a/LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs b/LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs
index 2cab50d5a..dd2ab2c37 100644
--- a/LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs
+++ b/LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs
@@ -298,6 +298,11 @@ private static RepositoryOptions BuildFakeRepositoryOptions(SelfCleaningDirector
         /// <param name="signature">The signature to use for user.name and user.email</param>
         /// <returns>The path to the configuration file</returns>
         protected string CreateConfigurationWithDummyUser(Signature signature)
+        {
+            return CreateConfigurationWithDummyUser(signature.Name, signature.Email);
+        }
+
+        protected string CreateConfigurationWithDummyUser(string name, string email)
         {
             SelfCleaningDirectory scd = BuildSelfCleaningDirectory();
             Directory.CreateDirectory(scd.DirectoryPath);
@@ -305,8 +310,15 @@ protected string CreateConfigurationWithDummyUser(Signature signature)
 
             using (Configuration config = new Configuration(configFilePath))
             {
-                config.Set("user.name", signature.Name, ConfigurationLevel.Global);
-                config.Set("user.email", signature.Email, ConfigurationLevel.Global);
+                if (name != null)
+                {
+                    config.Set("user.name", name, ConfigurationLevel.Global);
+                }
+
+                if (email != null)
+                {
+                    config.Set("user.email", email, ConfigurationLevel.Global);
+                }
             }
 
             return configFilePath;
diff --git a/LibGit2Sharp/Configuration.cs b/LibGit2Sharp/Configuration.cs
index 9e0a2633d..89059b63e 100644
--- a/LibGit2Sharp/Configuration.cs
+++ b/LibGit2Sharp/Configuration.cs
@@ -227,6 +227,7 @@ public virtual ConfigurationEntry<T> Get<T>(string key, ConfigurationLevel level
         /// <param name="level">The configuration file which should be considered as the target of this operation</param>
         public virtual void Set<T>(string key, T value, ConfigurationLevel level = ConfigurationLevel.Local)
         {
+            Ensure.ArgumentNotNull(value, "value");
             Ensure.ArgumentNotNullOrEmptyString(key, "key");
 
             using (ConfigurationSafeHandle h = RetrieveConfigurationHandle(level, true, configHandle))
@@ -341,30 +342,37 @@ public virtual Signature BuildSignature(DateTimeOffset now)
 
         internal Signature BuildSignature(DateTimeOffset now, bool shouldThrowIfNotFound)
         {
-            var name = Get<string>("user.name");
-            var email = Get<string>("user.email");
+            const string userNameKey = "user.name";
+            var name = this.GetValueOrDefault<string>(userNameKey);
+            var normalizedName = NormalizeUserSetting(shouldThrowIfNotFound, userNameKey, name,
+                () => "unknown");
+
+            const string userEmailKey = "user.email";
+            var email = this.GetValueOrDefault<string>(userEmailKey);
+            var normalizedEmail = NormalizeUserSetting(shouldThrowIfNotFound, userEmailKey, email,
+                () => string.Format(
+                    CultureInfo.InvariantCulture, "{0}@{1}", Environment.UserName, Environment.UserDomainName));
+
+            return new Signature(normalizedName, normalizedEmail, now);
+        }
 
-            if (shouldThrowIfNotFound)
+        private string NormalizeUserSetting(bool shouldThrowIfNotFound, string entryName, string currentValue, Func<string> defaultValue)
+        {
+            if (!string.IsNullOrEmpty(currentValue))
             {
-                if (name == null || string.IsNullOrEmpty(name.Value))
-                {
-                    throw new LibGit2SharpException(
-                        "Can not find Name setting of the current user in Git configuration.");
-                }
+                return currentValue;
+            }
 
-                if (email == null || string.IsNullOrEmpty(email.Value))
-                {
-                    throw new LibGit2SharpException(
-                        "Can not find Email setting of the current user in Git configuration.");
-                }
+            string message = string.Format("Configuration value '{0}' is missing or invalid.", entryName);
+
+            if (shouldThrowIfNotFound)
+            {
+                throw new LibGit2SharpException(message);
             }
 
-            var nameForSignature = name == null || string.IsNullOrEmpty(name.Value) ? "unknown" : name.Value;
-            var emailForSignature = email == null || string.IsNullOrEmpty(email.Value)
-                                        ? string.Format("{0}@{1}", Environment.UserName, Environment.UserDomainName)
-                                        : email.Value;
+            Log.Write(LogLevel.Warning, message);
 
-            return new Signature(nameForSignature, emailForSignature, now);
+            return defaultValue();
         }
 
         private ConfigurationSafeHandle Snapshot()
diff --git a/LibGit2Sharp/Signature.cs b/LibGit2Sharp/Signature.cs
index 74be26448..7dbb437d7 100644
--- a/LibGit2Sharp/Signature.cs
+++ b/LibGit2Sharp/Signature.cs
@@ -36,7 +36,7 @@ internal Signature(IntPtr signaturePtr)
         public Signature(string name, string email, DateTimeOffset when)
         {
             Ensure.ArgumentNotNullOrEmptyString(name, "name");
-            Ensure.ArgumentNotNull(email, "email");
+            Ensure.ArgumentNotNullOrEmptyString(email, "email");
             Ensure.ArgumentDoesNotContainZeroByte(name, "name");
             Ensure.ArgumentDoesNotContainZeroByte(email, "email");