--- a/ServerMonitor/Controls/HttpCheckControl.cs	Mon Dec 31 18:32:14 2018 -0500
+++ b/ServerMonitor/Controls/HttpCheckControl.cs	Tue Jan 01 21:14:47 2019 -0500
@@ -37,7 +37,14 @@
             HttpCheck check = (HttpCheck)check1;
             check.Url = UrlTextBox.Text.Trim();
             check.CheckResponseCode = ResponseCodeCheckBox.Checked;
-            check.ResponseCode = int.Parse(ResponseCodeTextBox.Text);
+            try
+            {
+                check.ResponseCode = int.Parse(ResponseCodeTextBox.Text);
+            }
+            catch
+            {
+                throw new UpdateCheckException("Response code must be an integer.");
+            }
             check.CheckResponseLength = ResponseLengthCheckbox.Checked;
             check.ResponseLengthMin = ResponseLengthMinTextBox.Text;
             check.ResponseLengthMax = ResponseLengthMaxTextBox.Text;