Replace direct calls to `explorer.exe` with the Shell API to prevent spawning an `explorer.exe` process that doesn't exit automatically on every call.

ILSpy/Commands/CreateDiagramContextMenuEntry.cs

@@ -75,7 +75,7 @@ namespace ICSharpCode.ILSpy.TextView
 				output.WriteLine();
 
 				var diagramHtml = Path.Combine(selectedPath, "index.html");
-				output.AddButton(null, Resources.OpenExplorer, delegate { Process.Start("explorer", "/select,\"" + diagramHtml + "\""); });
+				output.AddButton(null, Resources.OpenExplorer, delegate { ShellHelper.OpenFolderAndSelectItem(diagramHtml); });
 				output.WriteLine();
 				return output;
 			}, ct), Properties.Resources.CreatingDiagram).Then(dockWorkspace.ShowText).HandleExceptions();

ILSpy/Commands/ExtractPackageEntryContextMenuEntry.cs

@@ -161,7 +161,7 @@ namespace ICSharpCode.ILSpy
 				stopwatch.Stop();
 				output.WriteLine(Resources.GenerationCompleteInSeconds, stopwatch.Elapsed.TotalSeconds.ToString("F1"));
 				output.WriteLine();
-				output.AddButton(null, Resources.OpenExplorer, delegate { Process.Start("explorer", isFile ? $"/select,\"{path}\"" : $"\"{path}\""); });
+				output.AddButton(null, Resources.OpenExplorer, delegate { if (isFile) ShellHelper.OpenFolderAndSelectItem(path); else ShellHelper.OpenFolder(path); });
 				output.WriteLine();
 				return output;
 			}, ct)).Then(dockWorkspace.ShowText).HandleExceptions();

ILSpy/Commands/GeneratePdbContextMenuEntry.cs

@@ -112,7 +112,7 @@ namespace ICSharpCode.ILSpy
 				stopwatch.Stop();
 				output.WriteLine(Resources.GenerationCompleteInSeconds, stopwatch.Elapsed.TotalSeconds.ToString("F1"));
 				output.WriteLine();
-				output.AddButton(null, Resources.OpenExplorer, delegate { Process.Start("explorer", "/select,\"" + fileName + "\""); });
+				output.AddButton(null, Resources.OpenExplorer, delegate { ShellHelper.OpenFolderAndSelectItem(fileName); });
 				output.WriteLine();
 				return output;
 			}, ct)).Then(dockWorkspace.ShowText).HandleExceptions();
@@ -214,7 +214,19 @@ namespace ICSharpCode.ILSpy
 					output.WriteLine();
 					output.WriteLine(Resources.GenerationCompleteInSeconds, totalWatch.Elapsed.TotalSeconds.ToString("F1"));
 					output.WriteLine();
-					output.AddButton(null, Resources.OpenExplorer, delegate { Process.Start("explorer", "/select,\"" + targetFolder + "\""); });
+					// Select all generated pdb files in explorer
+					var generatedFiles = assemblyArray
+						.Select(a => Path.Combine(targetFolder, WholeProjectDecompiler.CleanUpFileName(a.ShortName, ".pdb")))
+						.Where(File.Exists)
+						.ToList();
+					if (generatedFiles.Any())
+					{
+						output.AddButton(null, Resources.OpenExplorer, delegate { ShellHelper.OpenFolderAndSelectItems(generatedFiles); });
+					}
+					else
+					{
+						output.AddButton(null, Resources.OpenExplorer, delegate { ShellHelper.OpenFolder(targetFolder); });
+					}
 					output.WriteLine();
 					return output;
 				}, ct)).Then(dockWorkspace.ShowText).HandleExceptions();

ILSpy/SolutionWriter.cs

@@ -187,7 +187,7 @@ namespace ICSharpCode.ILSpy
 				result.WriteLine();
 				result.WriteLine("Elapsed time: " + stopwatch.Elapsed.TotalSeconds.ToString("F1") + " seconds.");
 				result.WriteLine();
-				result.AddButton(null, "Open Explorer", delegate { Process.Start("explorer", "/select,\"" + solutionFilePath + "\""); });
+				result.AddButton(null, "Open Explorer", delegate { ShellHelper.OpenFolderAndSelectItem(solutionFilePath); });
 			}
 
 			return result;

ILSpy/TextView/DecompilerTextView.cs

@@ -1204,7 +1204,7 @@ namespace ICSharpCode.ILSpy.TextView
 							}
 						}
 						output.WriteLine();
-						output.AddButton(null, Properties.Resources.OpenExplorer, delegate { Process.Start("explorer", "/select,\"" + fileName + "\""); });
+						output.AddButton(null, Properties.Resources.OpenExplorer, delegate { ShellHelper.OpenFolderAndSelectItem(fileName); });
 						output.WriteLine();
 						tcs.SetResult(output);
 					}

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -696,7 +696,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				var path = node.LoadedAssembly.FileName;
 				if (File.Exists(path))
 				{
-					GlobalUtils.ExecuteCommand("explorer.exe", $"/select,\"{path}\"");
+					ShellHelper.OpenFolderAndSelectItem(path);
 				}
 			}
 		}

ILSpy/Util/ShellHelper.cs

@@ -0,0 +1,152 @@
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Linq;
+using System.Collections.Generic;
+
+namespace ICSharpCode.ILSpy.Util
+{
+	static class ShellHelper
+	{
+		[DllImport("shell32.dll", CharSet = CharSet.Unicode)]
+		static extern int SHParseDisplayName([MarshalAs(UnmanagedType.LPWStr)] string pszName, IntPtr pbc, out IntPtr ppidl, uint sfgaoIn, out uint psfgaoOut);
+
+		[DllImport("shell32.dll")]
+		static extern int SHOpenFolderAndSelectItems(IntPtr pidlFolder, uint cidl, [MarshalAs(UnmanagedType.LPArray)] IntPtr[] apidl, uint dwFlags);
+
+		[DllImport("shell32.dll")]
+		static extern IntPtr ILFindLastID(IntPtr pidl);
+
+		[DllImport("ole32.dll")]
+		static extern void CoTaskMemFree(IntPtr pv);
+
+		public static void OpenFolder(string folderPath)
+		{
+			try
+			{
+				if (string.IsNullOrEmpty(folderPath))
+					return;
+				if (!Directory.Exists(folderPath))
+					return;
+
+				IntPtr folderPidl = IntPtr.Zero;
+				uint attrs;
+				int hr = SHParseDisplayName(folderPath, IntPtr.Zero, out folderPidl, 0, out attrs);
+				if (hr == 0 && folderPidl != IntPtr.Zero)
+				{
+					SHOpenFolderAndSelectItems(folderPidl, 0, null, 0);
+					CoTaskMemFree(folderPidl);
+				}
+				else
+				{
+					// fallback
+					Process.Start(new ProcessStartInfo { FileName = folderPath, UseShellExecute = true });
+				}
+			}
+			catch
+			{
+				// ignore
+			}
+		}
+
+		public static void OpenFolderAndSelectItem(string path)
+		{
+			// Reuse the multi-item implementation for single item selection to avoid duplication.
+			try
+			{
+				if (string.IsNullOrEmpty(path))
+					return;
+				if (Directory.Exists(path))
+				{
+					OpenFolder(path);
+					return;
+				}
+
+				if (!File.Exists(path))
+					return;
+
+				OpenFolderAndSelectItems(new[] { path });
+			}
+			catch
+			{
+				// ignore
+			}
+		}
+
+		public static void OpenFolderAndSelectItems(IEnumerable<string> paths)
+		{
+			try
+			{
+				if (paths == null)
+					return;
+				// Group by containing folder
+				var files = paths.Where(p => !string.IsNullOrEmpty(p) && File.Exists(p)).ToList();
+				if (files.Count == 0)
+					return;
+
+				var groups = files.GroupBy(p => Path.GetDirectoryName(p));
+				foreach (var group in groups)
+				{
+					string folder = group.Key;
+					if (string.IsNullOrEmpty(folder) || !Directory.Exists(folder))
+						continue;
+
+					IntPtr folderPidl = IntPtr.Zero;
+					uint attrs;
+					int hrFolder = SHParseDisplayName(folder, IntPtr.Zero, out folderPidl, 0, out attrs);
+					if (hrFolder != 0 || folderPidl == IntPtr.Zero)
+					{
+						// fallback: open folder normally
+						OpenFolder(folder);
+						continue;
+					}
+
+					var itemPidlAllocs = new List<IntPtr>();
+					var relativePidls = new List<IntPtr>();
+					try
+					{
+						foreach (var file in group)
+						{
+							IntPtr itemPidl = IntPtr.Zero;
+							int hrItem = SHParseDisplayName(file, IntPtr.Zero, out itemPidl, 0, out attrs);
+							if (hrItem == 0 && itemPidl != IntPtr.Zero)
+							{
+								IntPtr relative = ILFindLastID(itemPidl);
+								if (relative != IntPtr.Zero)
+								{
+									relativePidls.Add(relative);
+									itemPidlAllocs.Add(itemPidl);
+									continue;
+								}
+							}
+							if (itemPidl != IntPtr.Zero)
+								CoTaskMemFree(itemPidl);
+						}
+
+						if (relativePidls.Count > 0)
+						{
+							SHOpenFolderAndSelectItems(folderPidl, (uint)relativePidls.Count, relativePidls.ToArray(), 0);
+						}
+						else
+						{
+							// nothing to select - open folder
+							OpenFolder(folder);
+						}
+					}
+					finally
+					{
+						foreach (var p in itemPidlAllocs)
+							CoTaskMemFree(p);
+						if (folderPidl != IntPtr.Zero)
+							CoTaskMemFree(folderPidl);
+					}
+				}
+			}
+			catch
+			{
+				// ignore
+			}
+		}
+	}
+}