diff --git a/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/CsvViewerPanel.xaml.cs b/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/CsvViewerPanel.xaml.cs
index 4c5a737..1b3e011 100644
--- a/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/CsvViewerPanel.xaml.cs
+++ b/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/CsvViewerPanel.xaml.cs
@@ -48,35 +48,51 @@ public partial class CsvViewerPanel : UserControl
         var encoding = CharsetDetector.DetectFromFile(path).Detected?.Encoding ??
                        Encoding.Default;
 
-        using (var sr = new StreamReader(new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite), encoding))
+        using var sr = new StreamReader(new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite), encoding);
+      
+        // Use fixed delimiters for known extensions to avoid mis-detection on small samples.
+        var extension = Path.GetExtension(path);
+        var delimiter = extension.Equals(".tsv", StringComparison.OrdinalIgnoreCase)
+            ? "\t"
+            : extension.Equals(".psv", StringComparison.OrdinalIgnoreCase)
+                ? "|"
+                : null;
+
+        var conf = new CsvConfiguration(CultureInfo.CurrentUICulture)
         {
-            var conf = new CsvConfiguration(CultureInfo.CurrentUICulture) { MissingFieldFound = null, BadDataFound = null, DetectDelimiter = true };
+            MissingFieldFound = null,
+            BadDataFound = null,
+            DetectDelimiter = delimiter == null,
+        };
 
-            using (var parser = new CsvParser(sr, conf))
+        if (delimiter != null)
+        {
+            // Force delimiter for TSV/PSV so CsvHelper doesn't auto-detect incorrectly.
+            conf.Delimiter = delimiter;
+        }
+
+        using var parser = new CsvParser(sr, conf);
+        var i = 0;
+        while (parser.Read())
+        {
+            var row = parser.Record;
+            if (row == null)
+                break;
+            row = Concat([$"{i++ + 1}".PadLeft(6)], row);
+
+            if (!binded)
             {
-                var i = 0;
-                while (parser.Read())
-                {
-                    var row = parser.Record;
-                    if (row == null)
-                        break;
-                    row = Concat([$"{i++ + 1}".PadLeft(6)], row);
-
-                    if (!binded)
-                    {
-                        SetupColumnBinding(row.Length);
-                        binded = true;
-                    }
-
-                    if (i > limit)
-                    {
-                        Rows.Add(Enumerable.Repeat("...", row.Length).ToArray());
-                        break;
-                    }
-
-                    Rows.Add(row);
-                }
+                SetupColumnBinding(row.Length);
+                binded = true;
             }
+
+            if (i > limit)
+            {
+                Rows.Add([.. Enumerable.Repeat("...", row.Length)]);
+                break;
+            }
+
+            Rows.Add(row);
         }
     }
 
diff --git a/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/Plugin.cs b/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/Plugin.cs
index 1cfc95e..152ca29 100644
--- a/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/Plugin.cs
+++ b/QuickLook.Plugin/QuickLook.Plugin.CsvViewer/Plugin.cs
@@ -34,7 +34,12 @@ public sealed class Plugin : IViewer
 
     public bool CanHandle(string path)
     {
-        return !Directory.Exists(path) && (path.ToLower().EndsWith(".csv") || path.ToLower().EndsWith(".tsv"));
+        if (Directory.Exists(path))
+            return false;
+
+        return path.EndsWith(".csv", StringComparison.OrdinalIgnoreCase)
+            || path.EndsWith(".tsv", StringComparison.OrdinalIgnoreCase)
+            || path.EndsWith(".psv", StringComparison.OrdinalIgnoreCase);
     }
 
     public void Prepare(string path, ContextObject context)