diff --git a/src/MarkPad/Preview/HtmlPreview.xaml.cs b/src/MarkPad/Preview/HtmlPreview.xaml.cs
index a69bb5e7..a37546b6 100644
--- a/src/MarkPad/Preview/HtmlPreview.xaml.cs
+++ b/src/MarkPad/Preview/HtmlPreview.xaml.cs
@@ -1,5 +1,6 @@
 using CefSharp;
 using System;
+using System.Web;
 using System.Windows;
 using System.Windows.Controls;
 
@@ -103,7 +104,7 @@ private static void HtmlChanged(DependencyObject d, DependencyPropertyChangedEve
             if (htmlPreview.host != null && htmlPreview.host.IsBrowserInitialized)
             {
                 var fileName = (htmlPreview.FileName ?? "blank").Replace(" ", "-");
-                var fileUrl = string.Format("http://{0}/", fileName);
+                var fileUrl = string.Format("http://{0}/", MakeUrlSegmentSafe(fileName));
 
                 var newValue = e.NewValue as string;
                 if (newValue == null)
@@ -157,7 +158,7 @@ private void Host_IsBrowserInitializedChanged(object sender, DependencyPropertyC
         private void InitializeData()
         {
             var fileName = (FileName ?? "blank").Replace(" ", "-");
-            var fileUrl = string.Format("http://{0}/", fileName);
+            var fileUrl = string.Format("http://{0}/", MakeUrlSegmentSafe(fileName));
 
             var html = Html ?? string.Empty;
 
@@ -181,5 +182,12 @@ public async void UpdateZoomLevel(double fontSize)
             });
             host.SetZoomLevel(fontSize * scale * 2 / Constants.FONT_SIZE_ENUM_ADJUSTMENT);
         }
+
+        private static string MakeUrlSegmentSafe(string urlSegment)
+        {
+            // it appears that the chromium web browser does not like parens or exclamations in a url
+            // replace these chars and also do a url path encode to try to avoid other potential problem chars
+            return HttpUtility.UrlEncode(urlSegment).Replace("(", "%28").Replace(")", "%29").Replace("!", "%21");
+        }
     }
 }
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