diff --git a/src/FlexLabs.EntityFrameworkCore.Upsert/HelpLinks.cs b/src/FlexLabs.EntityFrameworkCore.Upsert/HelpLinks.cs
index f469337..daf6a29 100644
--- a/src/FlexLabs.EntityFrameworkCore.Upsert/HelpLinks.cs
+++ b/src/FlexLabs.EntityFrameworkCore.Upsert/HelpLinks.cs
@@ -3,7 +3,9 @@
     internal class HelpLinks
     {
         internal const string Sqlite3Instructions = "https://go.flexlabs.org/upsert.sqlite3";
+        // Also referenced in the xml comment for InvalidMatchColumnsException
         internal const string IdentityKeyMatchError = "https://go.flexlabs.org/upsert.identitykeymatch";
+        // Also referenced in the xml comment for UnsupportedExpressionException
         // Also referenced in the xml comment for UpsertCommandBuilder.WithFallbackExpressionCompiler
         internal const string SupportedExpressions = "https://go.flexlabs.org/upsert.expressions";
     }
diff --git a/src/FlexLabs.EntityFrameworkCore.Upsert/InvalidMatchColumnsException.cs b/src/FlexLabs.EntityFrameworkCore.Upsert/InvalidMatchColumnsException.cs
index 7da4c38..b5342bc 100644
--- a/src/FlexLabs.EntityFrameworkCore.Upsert/InvalidMatchColumnsException.cs
+++ b/src/FlexLabs.EntityFrameworkCore.Upsert/InvalidMatchColumnsException.cs
@@ -4,9 +4,8 @@ namespace FlexLabs.EntityFrameworkCore.Upsert
 {
     /// <summary>
     /// Thrown when using unsupported columns as the upsert match expression.
-    /// See: https://flexlabs.org/plink/upsert.sqlite3
+    /// See: https://go.flexlabs.org/upsert.identitykeymatch
     /// </summary>
-    /// <seealso cref=""/>
     public sealed class InvalidMatchColumnsException : Exception
     {
         internal InvalidMatchColumnsException()
diff --git a/src/FlexLabs.EntityFrameworkCore.Upsert/UnsupportedExpressionException.cs b/src/FlexLabs.EntityFrameworkCore.Upsert/UnsupportedExpressionException.cs
index fca8703..65d62cc 100644
--- a/src/FlexLabs.EntityFrameworkCore.Upsert/UnsupportedExpressionException.cs
+++ b/src/FlexLabs.EntityFrameworkCore.Upsert/UnsupportedExpressionException.cs
@@ -4,6 +4,7 @@ namespace FlexLabs.EntityFrameworkCore.Upsert
 {
     /// <summary>
     /// Thrown when using unsupported expressions in the update clause
+    /// See: https://go.flexlabs.org/upsert.expressions
     /// </summary>
     public class UnsupportedExpressionException : Exception
     {
diff --git a/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/Tables.cs b/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/Tables.cs
index 0fa65fa..7998088 100644
--- a/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/Tables.cs
+++ b/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/Tables.cs
@@ -63,4 +63,30 @@ public class Status
         public string Name { get; set; }
         public DateTime LastChecked { get; set; }
     }
+
+    public class GuidKeyAutoGen
+    {
+        public Guid ID { get; set; }
+        public string Name { get; set; }
+    }
+
+    public class GuidKey
+    {
+        [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
+        public Guid ID { get; set; }
+        public string Name { get; set; }
+    }
+
+    public class StringKeyAutoGen
+    {
+        public string ID { get; set; }
+        public string Name { get; set; }
+    }
+
+    public class StringKey
+    {
+        [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
+        public string ID { get; set; }
+        public string Name { get; set; }
+    }
 }
diff --git a/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/TestDbContext.cs b/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/TestDbContext.cs
index 73510ca..1c1338c 100644
--- a/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/TestDbContext.cs
+++ b/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/Base/TestDbContext.cs
@@ -34,6 +34,10 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
         public DbSet<PageVisit> PageVisits { get; set; }
         public DbSet<SchemaTable> SchemaTable { get; set; }
         public DbSet<Status> Statuses { get; set; }
+        public DbSet<GuidKeyAutoGen> GuidKeysAutoGen { get; set; }
+        public DbSet<GuidKey> GuidKeys { get; set; }
+        public DbSet<StringKeyAutoGen> StringKeysAutoGen { get; set; }
+        public DbSet<StringKey> StringKeys { get; set; }
 
         public enum DbDriver
         {
diff --git a/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/BasicTest.cs b/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/BasicTest.cs
index c2d1d84..383bb8e 100644
--- a/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/BasicTest.cs
+++ b/test/FlexLabs.EntityFrameworkCore.Upsert.Tests/EF/BasicTest.cs
@@ -206,6 +206,10 @@ private void ResetDb(TestDbContext.DbDriver driver)
                 dbContext.SchemaTable.RemoveRange(dbContext.SchemaTable);
                 dbContext.PageVisits.RemoveRange(dbContext.PageVisits);
                 dbContext.Books.RemoveRange(dbContext.Books);
+                dbContext.GuidKeysAutoGen.RemoveRange(dbContext.GuidKeysAutoGen);
+                dbContext.GuidKeys.RemoveRange(dbContext.GuidKeys);
+                dbContext.StringKeysAutoGen.RemoveRange(dbContext.StringKeysAutoGen);
+                dbContext.StringKeys.RemoveRange(dbContext.StringKeys);
 
                 dbContext.Countries.Add(_dbCountry);
                 dbContext.PageVisits.Add(_dbVisitOld);
@@ -259,6 +263,25 @@ public void Upsert_InitialDbState(TestDbContext.DbDriver driver)
             }
         }
 
+        [Theory]
+        [MemberData(nameof(GetDatabaseEngines))]
+        public void Upsert_EFCore_KeyAutoGen(TestDbContext.DbDriver driver)
+        {
+            ResetDb(driver);
+            using (var dbContext = new TestDbContext(_dataContexts[driver]))
+            {
+                dbContext.GuidKeysAutoGen.Add(new GuidKeyAutoGen { Name = "test" });
+                dbContext.StringKeysAutoGen.Add(new StringKeyAutoGen { Name = "test" });
+                dbContext.SaveChanges();
+
+                // Ensuring EFCore generates empty values for Guid and string keys
+                Assert.Collection(dbContext.GuidKeysAutoGen,
+                    e => Assert.NotEqual(Guid.Empty, e.ID));
+                Assert.Collection(dbContext.StringKeysAutoGen,
+                    e => Assert.NotEmpty(e.ID));
+            }
+        }
+
         [Theory]
         [MemberData(nameof(GetDatabaseEngines))]
         public void Upsert_InvalidMatchColumn_NoOn(TestDbContext.DbDriver driver)
@@ -1251,5 +1274,89 @@ public void Upsert_JsonData(TestDbContext.DbDriver driver)
                     j => Assert.True(JToken.DeepEquals(JObject.Parse(newJson.Data), JObject.Parse(j.Data))));
             }
         }
+
+        [Theory]
+        [MemberData(nameof(GetDatabaseEngines))]
+        public void Upsert_GuidKey_AutoGenThrows(TestDbContext.DbDriver driver)
+        {
+            ResetDb(driver);
+            using (var dbContext = new TestDbContext(_dataContexts[driver]))
+            {
+                Assert.Throws<InvalidMatchColumnsException>(delegate
+                {
+                    var newItem = new GuidKeyAutoGen
+                    {
+                        ID = Guid.NewGuid(),
+                        Name = "test",
+                    };
+
+                    dbContext.GuidKeysAutoGen.Upsert(newItem)
+                        .Run();
+                });
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(GetDatabaseEngines))]
+        public void Upsert_StringKey_AutoGenThrows(TestDbContext.DbDriver driver)
+        {
+            ResetDb(driver);
+            using (var dbContext = new TestDbContext(_dataContexts[driver]))
+            {
+                Assert.Throws<InvalidMatchColumnsException>(delegate
+                {
+                    var newItem = new StringKeyAutoGen
+                    {
+                        ID = Guid.NewGuid().ToString(),
+                        Name = "test",
+                    };
+
+                    dbContext.StringKeysAutoGen.Upsert(newItem)
+                        .Run();
+                });
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(GetDatabaseEngines))]
+        public void Upsert_GuidKey(TestDbContext.DbDriver driver)
+        {
+            ResetDb(driver);
+            using (var dbContext = new TestDbContext(_dataContexts[driver]))
+            {
+                var newItem = new GuidKey
+                {
+                    ID = Guid.NewGuid(),
+                    Name = "test",
+                };
+
+                dbContext.GuidKeys.Upsert(newItem)
+                    .Run();
+
+                Assert.Collection(dbContext.GuidKeys.OrderBy(j => j.ID),
+                    j => Assert.Equal(newItem.ID, j.ID));
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(GetDatabaseEngines))]
+        public void Upsert_StringKey(TestDbContext.DbDriver driver)
+        {
+            ResetDb(driver);
+            using (var dbContext = new TestDbContext(_dataContexts[driver]))
+            {
+                var newItem = new StringKey
+                {
+                    ID = Guid.NewGuid().ToString(),
+                    Name = "test",
+                };
+
+                dbContext.StringKeys.Upsert(newItem)
+                    .Run();
+
+                Assert.Collection(dbContext.StringKeys.OrderBy(j => j.ID),
+                    j => Assert.Equal(newItem.ID, j.ID));
+            }
+        }
     }
 }