diff --git a/src/WindowController.App/SyncManager.cs b/src/WindowController.App/SyncManager.cs
index b67288b..726407a 100644
--- a/src/WindowController.App/SyncManager.cs
+++ b/src/WindowController.App/SyncManager.cs
@@ -118,6 +118,7 @@ public void UpdateHooksIfNeeded(bool skipRebuild = false)
         {
             _hookManager.Uninstall();
             _syncGroups.Clear();
+            _profileNames.Clear();
             _lastMinMaxByHwnd.Clear();
         }
     }
diff --git a/src/WindowController.App/ViewModels/MainViewModel.cs b/src/WindowController.App/ViewModels/MainViewModel.cs
index 1cc12b5..cea74d8 100644
--- a/src/WindowController.App/ViewModels/MainViewModel.cs
+++ b/src/WindowController.App/ViewModels/MainViewModel.cs
@@ -45,6 +45,7 @@ public partial class MainViewModel : ObservableObject
     private readonly SyncManager _syncManager;
     private readonly AppSettingsStore _appSettings;
     private readonly ILogger _log;
+    private bool _isUpdatingProfileName;
 
     [ObservableProperty] private string _statusText = "";
     [ObservableProperty] private string _profileName = "";
@@ -447,13 +448,36 @@ public void ReloadProfiles()
 
     private void OnProfileNameChanged(ProfileItem pi)
     {
+        // Prevent re-entrancy when we programmatically update pi.Name
+        if (_isUpdatingProfileName)
+            return;
+
+        // Get the current profile from the store
+        var current = _store.FindById(pi.Id);
+        if (current == null)
+        {
+            StatusText = "プロファイルが見つかりません。";
+            return;
+        }
+
+        // If the name has not actually changed compared to the store, ignore.
+        if (string.Equals(current.Name, pi.Name, StringComparison.Ordinal))
+            return;
+
+
         var newName = pi.Name?.Trim();
         if (string.IsNullOrEmpty(newName))
         {
             // Revert to current stored name
-            var current = _store.FindById(pi.Id);
-            if (current != null)
+            _isUpdatingProfileName = true;
+            try
+            {
                 pi.Name = current.Name;
+            }
+            finally
+            {
+                _isUpdatingProfileName = false;
+            }
             StatusText = "プロファイル名を空にすることはできません。";
             return;
         }
@@ -467,7 +491,17 @@ private void OnProfileNameChanged(ProfileItem pi)
 
         // If the name was adjusted due to conflict, update the UI
         if (finalName != newName)
-            pi.Name = finalName;
+        {
+            _isUpdatingProfileName = true;
+            try
+            {
+                pi.Name = finalName;
+            }
+            finally
+            {
+                _isUpdatingProfileName = false;
+            }
+        }
 
         _syncManager.ScheduleRebuild();
         StatusText = $"名前を変更しました: {finalName}";
diff --git a/src/WindowController.Core.Tests/ProfileStoreTests.cs b/src/WindowController.Core.Tests/ProfileStoreTests.cs
index d20aada..0076f21 100644
--- a/src/WindowController.Core.Tests/ProfileStoreTests.cs
+++ b/src/WindowController.Core.Tests/ProfileStoreTests.cs
@@ -17,7 +17,14 @@ public ProfileStoreTests()
 
     public void Dispose()
     {
-        try { Directory.Delete(_tempDir, true); } catch { }
+        try
+        {
+            Directory.Delete(_tempDir, true);
+        }
+        catch (Exception ex)
+        {
+            _log.Warning(ex, "Failed to delete temporary test directory {TempDir}", _tempDir);
+        }
     }
 
     private string TempFile() => Path.Combine(_tempDir, "profiles.json");
diff --git a/src/WindowController.Core/ProfileStore.cs b/src/WindowController.Core/ProfileStore.cs
index 98412e5..05224e9 100644
--- a/src/WindowController.Core/ProfileStore.cs
+++ b/src/WindowController.Core/ProfileStore.cs
@@ -62,15 +62,16 @@ public void Load()
         {
             var json = File.ReadAllText(_filePath);
             var parsed = JsonSerializer.Deserialize<ProfilesRoot>(json, JsonOptions);
+            
+            // Detect migration need before normalization
+            bool needsMigration = parsed != null && parsed.Profiles.Any(p => 
+                string.IsNullOrEmpty(p.Id) || 
+                parsed.Profiles.Count(x => x.Id == p.Id) > 1);
+            
             var normalized = NormalizeData(parsed ?? new ProfilesRoot());
-
-            // Check if any profile received a new Id during normalization (migration)
-            bool needsSave = json != null && normalized.Profiles.Any(p =>
-                !json.Contains($"\"id\": \"{p.Id}\"", StringComparison.Ordinal));
-
             Data = normalized;
 
-            if (needsSave)
+            if (needsMigration)
                 Save();
         }
         catch (Exception ex)
@@ -153,7 +154,13 @@ public bool DeleteProfileById(string id)
         var profile = FindById(profileId);
         if (profile == null) return null;
 
-        var finalName = ResolveUniqueName(desiredName, profileId);
+        var trimmed = desiredName.Trim();
+        var finalName = ResolveUniqueName(trimmed, profileId);
+        
+        // Skip save if the name hasn't actually changed
+        if (finalName == profile.Name)
+            return finalName;
+        
         profile.Name = finalName;
         profile.UpdatedAt = DateTime.Now.ToString("yyyy-MM-dd'T'HH:mm:ss");
         Save();