diff --git a/testing/mozharness/mozharness/mozilla/testing/testbase.py b/testing/mozharness/mozharness/mozilla/testing/testbase.py
index 8fb9be7c3c46..3253b1627d36 100755
--- a/testing/mozharness/mozharness/mozilla/testing/testbase.py
+++ b/testing/mozharness/mozharness/mozilla/testing/testbase.py
@@ -202,8 +202,10 @@ class TestingMixin(VirtualenvMixin, BuildbotMixin, ResourceMonitoringMixin,
                 self.warning("Can't figure out symbols_url from installer_url: %s!" %
                              self.installer_url)
 
-        else:
-            self.fatal("Can't figure out symbols_url without an installer_url!")
+        # If no symbols URL can be determined let minidump_stackwalk query the symbols.
+        # As of now this only works for Nightly and release builds.
+        if not self.symbols_url:
+            self.warning("No symbols_url found. Let minidump_stackwalk query for symbols.")
 
         return self.symbols_url