fix: harden WMI/event-log error handling in health score, memory check, and known folders

CHANGELOG.md

@@ -6,6 +6,13 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+## [1.20.40] - 2026-06-17
+
+### Fixed
+- **The Health Score no longer fails outright when a system query hits a transient WMI error.** A repository or RPC fault while reading system info, disk health, or battery could throw an error the score didn't handle, failing the whole calculation; each source now degrades gracefully and the score is still produced from the rest.
+- **The memory-error check no longer counts a *passing* memory test as an error.** It counted every Windows Memory Diagnostic result, including the "no errors found" result (event 1101), as a problem; it now counts only the actual error result (event 1201).
+- **Known-folder lookup (Downloads, Documents, etc.) now falls back correctly when the system call fails.** The call's failure code was being ignored, so a failed lookup could return an empty path instead of using the standard fallback location; the result is now checked and the fallback applies.
+
 ## [1.20.39] - 2026-06-17
 
 ### Fixed

SysManager/SysManager/Helpers/KnownFolders.cs

@@ -23,7 +23,7 @@ internal static partial class KnownFolders
     private static readonly Guid Videos = new("18989B1D-99B5-455B-841C-AB7C74E4DDFC");
 
     [LibraryImport("shell32.dll", StringMarshalling = StringMarshalling.Utf16)]
-    private static partial void SHGetKnownFolderPath(
+    private static partial int SHGetKnownFolderPath(
         in Guid rfid,
         uint dwFlags,
         nint hToken,
@@ -49,27 +49,33 @@ private static partial void SHGetKnownFolderPath(
 
     private static string GetPath(Guid folderId)
     {
+        // The import returns the HRESULT. Because this is a plain (non-COM-interface)
+        // LibraryImport, a failure does NOT throw — it returns a non-zero HRESULT and a
+        // null/empty path. Check the HRESULT (and guard the path) and fall back to the
+        // SpecialFolder equivalent on any failure.
         try
         {
-            SHGetKnownFolderPath(folderId, 0, nint.Zero, out var path);
-            return path;
-        }
-        catch (COMException)
-        {
-            // Fallback to Environment.SpecialFolder if P/Invoke fails
-            return folderId == Downloads
-                ? Path.Join(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Downloads")
-                : folderId == Documents
-                ? Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
-                : folderId == Desktop
-                ? Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
-                : folderId == Pictures
-                ? Environment.GetFolderPath(Environment.SpecialFolder.MyPictures)
-                : folderId == Music
-                ? Environment.GetFolderPath(Environment.SpecialFolder.MyMusic)
-                : folderId == Videos
-                ? Environment.GetFolderPath(Environment.SpecialFolder.MyVideos)
-                : string.Empty;
+            int hr = SHGetKnownFolderPath(folderId, 0, nint.Zero, out var path);
+            if (hr >= 0 && !string.IsNullOrEmpty(path))
+                return path;
         }
+        catch (COMException) { /* fall through to the SpecialFolder fallback below */ }
+
+        return Fallback(folderId);
     }
+
+    private static string Fallback(Guid folderId) =>
+        folderId == Downloads
+            ? Path.Join(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Downloads")
+            : folderId == Documents
+            ? Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
+            : folderId == Desktop
+            ? Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
+            : folderId == Pictures
+            ? Environment.GetFolderPath(Environment.SpecialFolder.MyPictures)
+            : folderId == Music
+            ? Environment.GetFolderPath(Environment.SpecialFolder.MyMusic)
+            : folderId == Videos
+            ? Environment.GetFolderPath(Environment.SpecialFolder.MyVideos)
+            : string.Empty;
 }

SysManager/SysManager/Services/HealthScoreService.cs

@@ -47,16 +47,22 @@ public async Task<HealthScoreResult> ComputeAsync(CancellationToken ct = default
         IReadOnlyList<DiskHealthReport>? disks = null;
         BatteryInfo? battery = null;
 
+        // WMI enumeration (Get()) can throw COMException on repository/RPC failures, not
+        // just ManagementException — without this arm a transient WMI fault crashes the
+        // whole health score instead of degrading to a partial result.
         try { snapshot = await sysTask.ConfigureAwait(false); }
         catch (System.Management.ManagementException ex) { Log.Warning("HealthScore: system info failed: {Error}", ex.Message); }
+        catch (System.Runtime.InteropServices.COMException ex) { Log.Warning("HealthScore: system info WMI COM error: 0x{HResult:X8}", ex.HResult); }
         catch (InvalidOperationException ex) { Log.Warning("HealthScore: system info failed: {Error}", ex.Message); }
 
         try { disks = await diskTask.ConfigureAwait(false); }
         catch (System.Management.ManagementException ex) { Log.Warning("HealthScore: disk health failed: {Error}", ex.Message); }
+        catch (System.Runtime.InteropServices.COMException ex) { Log.Warning("HealthScore: disk health WMI COM error: 0x{HResult:X8}", ex.HResult); }
         catch (InvalidOperationException ex) { Log.Warning("HealthScore: disk health failed: {Error}", ex.Message); }
 
         try { battery = await batteryTask.ConfigureAwait(false); }
         catch (System.Management.ManagementException ex) { Log.Warning("HealthScore: battery failed: {Error}", ex.Message); }
+        catch (System.Runtime.InteropServices.COMException ex) { Log.Warning("HealthScore: battery WMI COM error: 0x{HResult:X8}", ex.HResult); }
         catch (InvalidOperationException ex) { Log.Warning("HealthScore: battery failed: {Error}", ex.Message); }
 
         // Compute component scores

SysManager/SysManager/Services/MemoryTestService.cs

@@ -40,25 +40,39 @@ public async Task<MemoryErrorSummary> CheckErrorLogsAsync(CancellationToken ct =
                     { ReverseDirection = true });
 
                 var cutoff = DateTime.Now.AddDays(-30);
-                System.Diagnostics.Eventing.Reader.EventRecord? rec;
-                while ((rec = reader.ReadEvent()) != null && !ct.IsCancellationRequested)
+                // Check cancellation BEFORE reading so a record read at the moment of
+                // cancellation isn't left to the GC; the read result is always wrapped
+                // in using(rec) below.
+                while (!ct.IsCancellationRequested && reader.ReadEvent() is { } rec)
                 {
                     using (rec)
                     {
                         if (rec.TimeCreated.HasValue && rec.TimeCreated.Value < cutoff) break;
 
                         var provider = rec.ProviderName ?? "";
+                        bool counted = false;
                         if (provider.Contains("WHEA"))
                         {
                             // Memory-related WHEA events are ID 17 / 18 / 19 / 20 typically
                             if (rec.Id == 17 || rec.Id == 18 || rec.Id == 19 || rec.Id == 20)
+                            {
                                 wheaCount++;
+                                counted = true;
+                            }
                         }
                         else if (provider.Contains("MemoryDiagnostics"))
                         {
-                            diagCount++;
+                            // 1201 = errors detected. 1101 = test passed (no errors), which
+                            // must NOT count as a memory error (previously any ID counted,
+                            // turning a clean test into a false warning).
+                            if (rec.Id == 1201)
+                            {
+                                diagCount++;
+                                counted = true;
+                            }
                         }
-                        if (rec.TimeCreated.HasValue && (lastError is null || rec.TimeCreated.Value > lastError))
+                        // Only advance lastError for records that actually count as errors.
+                        if (counted && rec.TimeCreated.HasValue && (lastError is null || rec.TimeCreated.Value > lastError))
                             lastError = rec.TimeCreated.Value;
                     }
                 }

SysManager/SysManager/SysManager.csproj

@@ -10,9 +10,9 @@
     <RootNamespace>SysManager</RootNamespace>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <NoWarn>NU1603;NU1701</NoWarn>
-    <Version>1.20.39</Version>
-    <FileVersion>1.20.39.0</FileVersion>
-    <AssemblyVersion>1.20.39.0</AssemblyVersion>
+    <Version>1.20.40</Version>
+    <FileVersion>1.20.40.0</FileVersion>
+    <AssemblyVersion>1.20.40.0</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>