diff --git a/TransactionProcessor.DatabaseTests/ContractEventTests.cs b/TransactionProcessor.DatabaseTests/ContractEventTests.cs
index 4251350..3192684 100644
--- a/TransactionProcessor.DatabaseTests/ContractEventTests.cs
+++ b/TransactionProcessor.DatabaseTests/ContractEventTests.cs
@@ -171,5 +171,25 @@ public async Task AddEstate_EventReplayHandled()
             result = await this.Repository.AddEstate(TestData.DomainEvents.EstateCreatedEvent, CancellationToken.None);
             result.IsSuccess.ShouldBeTrue();
         }
+
+        [Fact]
+        public async Task AddEstateSecurityUser_EstateIsAdded()
+        {
+            Result result = await this.Repository.AddEstateSecurityUser(TestData.DomainEvents.EstateSecurityUserAddedEvent, CancellationToken.None);
+            result.IsSuccess.ShouldBeTrue();
+            EstateManagementContext context = this.GetContext();
+            var estateSecurityUser = await context.EstateSecurityUsers.SingleOrDefaultAsync(f => f.EstateId == TestData.DomainEvents.EstateSecurityUserAddedEvent.EstateId && f.SecurityUserId == TestData.DomainEvents.EstateSecurityUserAddedEvent.SecurityUserId);
+            estateSecurityUser.ShouldNotBeNull();
+        }
+
+        [Fact]
+        public async Task AddEstateSecurityUser_EventReplayHandled()
+        {
+            Result result = await this.Repository.AddEstateSecurityUser(TestData.DomainEvents.EstateSecurityUserAddedEvent, CancellationToken.None);
+            result.IsSuccess.ShouldBeTrue();
+
+            result = await this.Repository.AddEstateSecurityUser(TestData.DomainEvents.EstateSecurityUserAddedEvent, CancellationToken.None);
+            result.IsSuccess.ShouldBeTrue();
+        }
     }
 }
diff --git a/TransactionProcessor.Repository/ITransactionProcessorReadModelRepository.cs b/TransactionProcessor.Repository/ITransactionProcessorReadModelRepository.cs
index 7db530b..ddb960a 100644
--- a/TransactionProcessor.Repository/ITransactionProcessorReadModelRepository.cs
+++ b/TransactionProcessor.Repository/ITransactionProcessorReadModelRepository.cs
@@ -993,7 +993,7 @@ public async Task<Result> AddEstateSecurityUser(EstateDomainEvents.SecurityUserA
 
             await context.EstateSecurityUsers.AddAsync(estateSecurityUser, cancellationToken);
 
-            return await context.SaveChangesAsync(cancellationToken);
+            return await context.SaveChangesWithDuplicateHandling(cancellationToken);
         }
 
         public async Task<Result> AddProductDetailsToTransaction(TransactionDomainEvents.ProductDetailsAddedToTransactionEvent domainEvent,