diff --git a/test/EventStore.Client.Streams.Tests/Security/SecurityFixture.cs b/test/EventStore.Client.Streams.Tests/Security/SecurityFixture.cs
index ad21b3e4f..72ab1ba9b 100644
--- a/test/EventStore.Client.Streams.Tests/Security/SecurityFixture.cs
+++ b/test/EventStore.Client.Streams.Tests/Security/SecurityFixture.cs
@@ -20,6 +20,8 @@ public abstract class SecurityFixture : EventStoreClientFixture {
 		public EventStoreUserManagementClient UserManagementClient { get; }
 
 		protected SecurityFixture() {
+			// make sure credentials aren't changing the test results./
+			Settings.DefaultCredentials = null;
 			UserManagementClient = new EventStoreUserManagementClient(Settings);
 		}
 
diff --git a/test/EventStore.Client.Tests.Common/EventStoreClientExtensions.cs b/test/EventStore.Client.Tests.Common/EventStoreClientExtensions.cs
index bf31c6359..ad3e2e274 100644
--- a/test/EventStore.Client.Tests.Common/EventStoreClientExtensions.cs
+++ b/test/EventStore.Client.Tests.Common/EventStoreClientExtensions.cs
@@ -26,7 +26,7 @@ await self.WarmUpWith(async cancellationToken => {
 
 				// the read from leader above is not enough to guarantee the next write goes to leader
 				await self.AppendToStreamAsync($"warmup", StreamState.Any, Enumerable.Empty<EventData>(),
-					cancellationToken: cancellationToken);
+					userCredentials: TestCredentials.Root, cancellationToken: cancellationToken);
 			});
 		}