Skip missing search directories to fix preloader DirectoryNotFoundException (#1331)

BepInEx.Core/Utility.cs

@@ -6,6 +6,7 @@ using System.Reflection;
 using System.Reflection.Emit;
 using System.Security.Cryptography;
 using System.Text;
+using BepInEx.Logging;
 using Mono.Cecil;
 
 namespace BepInEx;
@@ -416,12 +417,22 @@ public static class Utility
     {
         var result = new Dictionary<string, string>(StringComparer.InvariantCultureIgnoreCase);
         foreach (var directory in directories)
+        {
+            // A configured search directory (e.g. a missing unstripped_corlib) may not exist; warn and skip it
+            // instead of letting Directory.GetFiles throw DirectoryNotFoundException.
+            if (!Directory.Exists(directory))
+            {
+                Logger.Log(LogLevel.Warning, $"Skipping search directory that does not exist: {directory}");
+                continue;
+            }
+
             foreach (var file in Directory.GetFiles(directory, pattern))
             {
                 var fileName = Path.GetFileName(file);
                 if (!result.ContainsKey(fileName))
                     result[fileName] = file;
             }
+        }
 
         return result.Values;
     }