diff --git a/src/ClaudeDo.Installer/Pages/InstallPage/InstallPageViewModel.cs b/src/ClaudeDo.Installer/Pages/InstallPage/InstallPageViewModel.cs
index 9f46f68..3d6edad 100644
--- a/src/ClaudeDo.Installer/Pages/InstallPage/InstallPageViewModel.cs
+++ b/src/ClaudeDo.Installer/Pages/InstallPage/InstallPageViewModel.cs
@@ -84,6 +84,15 @@ public partial class InstallPageViewModel : ObservableObject, IInstallerPage
     {
         if (IsInstalling) return;
 
+        // Reset per-step state so a re-run starts clean instead of appending
+        // output to the previous run's messages.
+        foreach (var s in Steps)
+        {
+            s.Messages.Clear();
+            s.Status = StepStatus.Pending;
+            s.IsExpanded = false;
+        }
+
         IsInstalling = true;
         IsComplete = false;
         HasErrors = false;
@@ -96,7 +105,11 @@ public partial class InstallPageViewModel : ObservableObject, IInstallerPage
             var step = Steps.FirstOrDefault(s => s.Name == p.StepName);
             if (step is null) return;
 
-            step.Status = p.Status;
+            // Status and output lines arrive on two separate Progress<T> channels, so a
+            // trailing "Running" line-message can be delivered after the step's terminal
+            // Done/Failed. Never let that downgrade a completed step back to Running.
+            if (!(step.Status is StepStatus.Done or StepStatus.Failed && p.Status is StepStatus.Running))
+                step.Status = p.Status;
             if (p.Message is not null)
             {
                 // Messages starting with "\r" overwrite the previous line (live progress).