diff --git a/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaAuthorizer.java b/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaAuthorizer.java
index cd599fa51..9b0535572 100644
--- a/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaAuthorizer.java
+++ b/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaAuthorizer.java
@@ -84,7 +84,7 @@ public class ArchivaAuthorizer
                     authorizationException = e;
                 }
 
-                if ( result.isAuthorized() )
+                if ( result != null && result.isAuthorized() )
                 {
                     return result;
                 }
diff --git a/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaConfigurableUsersManager.java b/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaConfigurableUsersManager.java
index a87a4c433..853b14d15 100644
--- a/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaConfigurableUsersManager.java
+++ b/archiva-modules/archiva-web/archiva-web-common/src/main/java/org/apache/archiva/web/security/ArchivaConfigurableUsersManager.java
@@ -449,7 +449,7 @@ public class ArchivaConfigurableUsersManager
         throws UserManagerException
     {
         UserManager userManager = findFirstWritable();
-        if ( userManager.isReadOnly() )
+        if ( userManager == null )
         {
             log.warn( "cannot find writable user manager implementation, skip guest user creation" );
             return null;