fix: protect IFEO debugger and confirm privacy registry writes

CHANGELOG.md

@@ -6,6 +6,12 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+## [1.20.1] - 2026-06-08
+
+### Fixed
+- **App Blocker no longer clobbers a pre-existing debugger.** `BlockApp` wrote its IFEO `Debugger` value unconditionally, overwriting any value already present — which could break a legitimately-debugged application and was unrecoverable (Unblock only removes SysManager's own value). It now refuses to block an executable that already has an external `Debugger` set, leaving the existing configuration intact.
+- **Privacy changes now require confirmation.** Applying pending privacy toggles to the registry now prompts with `DialogService.Confirm` first, stating how many changes will be written and how to revert. Declining keeps the changes pending and writes nothing.
+
 ## [1.20.0] - 2026-06-08
 
 ### Added

SysManager/SysManager.Tests/PrivacyViewModelTests.cs

@@ -2,6 +2,7 @@
 // Author: laurentiu021 · https://github.com/laurentiu021/SystemManager
 // License: MIT
 
+using NSubstitute;
 using SysManager.Services;
 using SysManager.ViewModels;
 
@@ -135,4 +136,30 @@ public void ApplyChanges_WithNoPending_SetsNoChangesMessage()
 
         Assert.Contains("no changes", vm.StatusMessage, StringComparison.OrdinalIgnoreCase);
     }
+
+    [Fact]
+    public void ApplyChanges_WhenUserDeclinesConfirm_DoesNotApply_AndKeepsPending()
+    {
+        var prevDialog = DialogService.Instance;
+        var dialog = Substitute.For<IDialogService>();
+        dialog.Confirm(Arg.Any<string>(), Arg.Any<string>()).Returns(false); // user clicks "No"
+        DialogService.Instance = dialog;
+        try
+        {
+            var vm = CreateVm();
+            vm.Toggles[0].IsEnabled = !vm.Toggles[0].IsEnabled; // create a pending change
+            var pendingBefore = vm.PendingChangeCount;
+
+            vm.ApplyChangesCommand.Execute(null);
+
+            dialog.Received(1).Confirm(Arg.Any<string>(), Arg.Any<string>());
+            // Declining must NOT write to the registry: the change is still pending.
+            Assert.Equal(pendingBefore, vm.PendingChangeCount);
+            Assert.Contains("cancelled", vm.StatusMessage, StringComparison.OrdinalIgnoreCase);
+        }
+        finally
+        {
+            DialogService.Instance = prevDialog;
+        }
+    }
 }

SysManager/SysManager/Services/AppBlockerService.cs

@@ -45,6 +45,19 @@ public static bool BlockApp(string exeName)
             if (ifeo is null) return false;
 
             using var appKey = ifeo.CreateSubKey(exeName, writable: true);
+
+            // Never clobber a pre-existing Debugger value we did not set: it could
+            // belong to a legitimately-debugged app, and overwriting it would both
+            // break that setup and be unrecoverable (Unblock only removes OUR value).
+            var existingDebugger = appKey.GetValue("Debugger") as string;
+            if (!string.IsNullOrEmpty(existingDebugger) &&
+                !existingDebugger.Equals(BlockerDebugger, StringComparison.OrdinalIgnoreCase))
+            {
+                Log.Warning("Refusing to block {ExeName}: an external Debugger value is already set ({Debugger})",
+                    exeName, existingDebugger);
+                return false;
+            }
+
             appKey.SetValue("Debugger", BlockerDebugger, RegistryValueKind.String);
 
             Log.Information("Blocked application: {ExeName}", exeName);

SysManager/SysManager/SysManager.csproj

@@ -10,9 +10,9 @@
     <RootNamespace>SysManager</RootNamespace>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <NoWarn>NU1603;NU1701</NoWarn>
-    <Version>1.20.0</Version>
-    <FileVersion>1.20.0.0</FileVersion>
-    <AssemblyVersion>1.20.0.0</AssemblyVersion>
+    <Version>1.20.1</Version>
+    <FileVersion>1.20.1.0</FileVersion>
+    <AssemblyVersion>1.20.1.0</AssemblyVersion>
     <Product>SysManager</Product>
     <Description>SysManager — Windows system monitoring toolkit by laurentiu021. Network, updates, health, logs, safe deep cleanup.</Description>
     <PackageProjectUrl>https://github.com/laurentiu021/SystemManager</PackageProjectUrl>

SysManager/SysManager/ViewModels/PrivacyViewModel.cs

@@ -117,6 +117,15 @@ private void ApplyChanges()
             .Where(t => _baselineStates.TryGetValue(t, out var baseline) && baseline != t.IsEnabled)
             .ToList();
 
+        if (!DialogService.Instance.Confirm(
+                $"Apply {changed.Count} privacy change{(changed.Count == 1 ? "" : "s")} to the Windows registry?\n\n" +
+                "Each toggle can be reverted by switching it back and pressing Apply again.",
+                "Confirm Privacy Changes"))
+        {
+            StatusMessage = "Apply cancelled.";
+            return;
+        }
+
         _service.ApplyAll(changed);
 
         // Refresh baseline to the just-applied state.