diff --git a/letsencrypt-apache/letsencrypt_apache/configurator.py b/letsencrypt-apache/letsencrypt_apache/configurator.py
index 00b93bb6e..0c4d65c28 100644
--- a/letsencrypt-apache/letsencrypt_apache/configurator.py
+++ b/letsencrypt-apache/letsencrypt_apache/configurator.py
@@ -180,8 +180,11 @@ class ApacheConfigurator(augeas_configurator.AugeasConfigurator):
         regexp matching"""
 
         self.aug.set("/test/path/testing/arg", "aRgUMeNT")
-        matches = self.aug.match(
-            "/test//*[self::arg=~regexp('argument', 'i')]")
+        try:
+            matches = self.aug.match(
+                "/test//*[self::arg=~regexp('argument', 'i')]")
+        except RuntimeError:
+            return None
         self.aug.remove("/test/path")
         return matches