diff --git a/src/ServiceControl.Config.Tests/InstanceDetails/CorruptInstanceConfiguration.cs b/src/ServiceControl.Config.Tests/InstanceDetails/CorruptInstanceConfiguration.cs
index 5245eac65a..c96a82ac60 100644
--- a/src/ServiceControl.Config.Tests/InstanceDetails/CorruptInstanceConfiguration.cs
+++ b/src/ServiceControl.Config.Tests/InstanceDetails/CorruptInstanceConfiguration.cs
@@ -253,6 +253,7 @@ public async Task The_one_where_the_fix_is_picked_up_through_the_deployed_instan
                 {
                     EventAggregator = new EventAggregator()
                 };
+                await ((IActivate)list).ActivateAsync(TestContext.CurrentContext.CancellationToken);
                 Assert.That(list.HasConfigurationErrors, Is.True, "Precondition: the list starts out with a corrupt instance");
 
                 // The operator fixes the file, then triggers the refresh the UI uses
@@ -294,12 +295,12 @@ public void The_one_where_a_refresh_tries_to_apply_data_from_an_instance_of_a_di
         public class Rule_5_Must_summarize_configuration_errors_above_the_instance_list : CorruptInstanceConfigurationFixture
         {
             [Test]
-            public void The_one_where_a_single_instance_is_corrupt_and_the_banner_names_it()
+            public async Task The_one_where_a_single_instance_is_corrupt_and_the_banner_names_it()
             {
                 WriteErrorInstanceConfig(CorruptXml);
                 WriteAuditInstanceConfig(ValidAuditInstanceXml);
 
-                var list = ListFor(LoadErrorInstance(), LoadAuditInstance("Particular.ServiceControl.Audit"));
+                var list = await ListFor(LoadErrorInstance(), LoadAuditInstance("Particular.ServiceControl.Audit"));
 
                 using (Assert.EnterMultipleScope())
                 {
@@ -310,23 +311,23 @@ public void The_one_where_a_single_instance_is_corrupt_and_the_banner_names_it()
             }
 
             [Test]
-            public void The_one_where_multiple_instances_are_corrupt_and_the_banner_lists_all_of_them()
+            public async Task The_one_where_multiple_instances_are_corrupt_and_the_banner_lists_all_of_them()
             {
                 WriteErrorInstanceConfig(CorruptXml);
                 WriteAuditInstanceConfig(CorruptXml);
 
-                var list = ListFor(LoadErrorInstance(), LoadAuditInstance("Particular.ServiceControl.Audit"));
+                var list = await ListFor(LoadErrorInstance(), LoadAuditInstance("Particular.ServiceControl.Audit"));
 
                 Assert.That(list.ConfigurationErrorMessage,
                     Is.EqualTo("Multiple instances (Particular.ServiceControl, Particular.ServiceControl.Audit) cannot be loaded due to XML configuration errors."));
             }
 
             [Test]
-            public void The_one_where_all_configurations_are_valid_and_no_banner_is_shown()
+            public async Task The_one_where_all_configurations_are_valid_and_no_banner_is_shown()
             {
                 WriteErrorInstanceConfig(ValidErrorInstanceXml);
 
-                var list = ListFor(LoadErrorInstance());
+                var list = await ListFor(LoadErrorInstance());
 
                 using (Assert.EnterMultipleScope())
                 {
@@ -400,8 +401,15 @@ protected MonitoringInstance LoadMonitoringInstance(string serviceName = Service
         internal static InstanceDetailsViewModel DetailsFor(BaseService instance) =>
             new(instance, null, null, null, null, null, null, null, null);
 
-        internal static ListInstancesViewModel ListFor(params BaseService[] instances) =>
-            new(DetailsFor, () => instances);
+        // The list populates in OnInitialize, so it has to be activated before it has anything in it
+#pragma warning disable PS0018 // A params array must be the last parameter, so a trailing CancellationToken cannot be added
+        internal static async Task<ListInstancesViewModel> ListFor(params BaseService[] instances)
+#pragma warning restore PS0018
+        {
+            var list = new ListInstancesViewModel(DetailsFor, () => instances);
+            await ((IActivate)list).ActivateAsync(TestContext.CurrentContext.CancellationToken);
+            return list;
+        }
 
         class FakeWindowsServiceController(string exePath, string serviceName) : IWindowsServiceController
         {
diff --git a/src/ServiceControl.Config/UI/ListInstances/ListInstancesViewModel.cs b/src/ServiceControl.Config/UI/ListInstances/ListInstancesViewModel.cs
index bb89720cd6..6ec76f53f2 100644
--- a/src/ServiceControl.Config/UI/ListInstances/ListInstancesViewModel.cs
+++ b/src/ServiceControl.Config/UI/ListInstances/ListInstancesViewModel.cs
@@ -32,10 +32,10 @@ internal ListInstancesViewModel(Func<BaseService, InstanceDetailsViewModel> inst
             CopyToClipboard = new CopyToClipboardCommand();
 
             Instances = [];
-
-            AddAndRemoveInstances();
         }
 
+        protected override Task OnInitialize(CancellationToken cancellationToken = default) => AddAndRemoveInstances(cancellationToken);
+
         public CopyToClipboardCommand CopyToClipboard { get; }
 
         public BindableCollection<InstanceDetailsViewModel> OrderedInstances => [.. Instances.OrderBy(x => x.Name)];
@@ -107,7 +107,7 @@ public Task HandleAsync(LicenseUpdated licenseUpdatedEvent, CancellationToken ca
         /// </summary>
         public async Task HandleAsync(RefreshInstances message, CancellationToken cancellationToken = default)
         {
-            AddAndRemoveInstances();
+            await AddAndRemoveInstances(cancellationToken);
             await EventAggregator.PublishOnUIThreadAsync(new PostRefreshInstances(), cancellationToken);
         }
 
@@ -127,12 +127,7 @@ public async Task HandleAsync(ResetInstances message, CancellationToken cancella
             NotifyOfPropertyChange(nameof(Instances));
         }
 
-        // TODO: this is a genuine async void, not an event handler. Because it returns at the first
-        // await, HandleAsync(RefreshInstances) publishes PostRefreshInstances before the removals have
-        // finished, which is the ordering that method's own remarks say must not happen. Converting it
-        // to async Task needs the constructor call site at the top of this class restructured first.
-#pragma warning disable PS0027
-        async void AddAndRemoveInstances()
+        async Task AddAndRemoveInstances(CancellationToken cancellationToken)
         {
             // Remove instances that no longer exist on disk
             var toRemove = Instances.Where(instance => !instance.Exists()).ToList();
@@ -169,7 +164,6 @@ async void AddAndRemoveInstances()
             NotifyOfPropertyChange(nameof(HasConfigurationErrors));
             NotifyOfPropertyChange(nameof(ConfigurationErrorMessage));
         }
-#pragma warning restore PS0027
 
         readonly Func<BaseService, InstanceDetailsViewModel> instanceDetailsFunc;
         readonly Func<IEnumerable<BaseService>> getAllInstances;