diff --git a/src/Util/U.php b/src/Util/U.php
index d64abcb1..4545f712 100644
--- a/src/Util/U.php
+++ b/src/Util/U.php
@@ -413,6 +413,7 @@ public static function success_out($output) {
     // http://stackoverflow.com/questions/834303/startswith-and-endswith-public static functions-in-php
     public static function startsWith($haystack, $needle) {
         // search backwards starting from haystack length characters from the end
+        if ( !is_string($haystack) || !is_string($needle) ) return false;
         return $needle === "" || strrpos($haystack, $needle, -strlen($haystack)) !== FALSE;
     }
 
diff --git a/tests/Util/UTest.php b/tests/Util/UTest.php
index 1d1d7b4d..532283ce 100644
--- a/tests/Util/UTest.php
+++ b/tests/Util/UTest.php
@@ -306,6 +306,17 @@ public function testSha256() {
         $this->assertEquals($out, null);
     }
 
+    public function testStartsWith() {
+        $this->assertTrue(U::startsWith("csev@umich.edu", "csev"));
+        $this->assertTrue(U::startsWith("csev@umich.edu", ""));
+        $this->assertFalse(U::startsWith("csev@umich.edu", "cxev"));
+        $this->assertFalse(U::startsWith("edu", "@umich.edu"));
+        $this->assertFalse(U::startsWith(null, "@umich.edu"));
+        $this->assertFalse(U::startsWith(null, null));
+        $this->assertFalse(U::startsWith("edu", null));
+    }
+
+
     public function testEndsWith() {
         $this->assertTrue(U::endsWith("csev@umich.edu", "@umich.edu"));
         $this->assertTrue(U::endsWith("csev@umich.edu", ""));