diff --git a/source/java/org/alfresco/repo/site/SiteServiceImpl.java b/source/java/org/alfresco/repo/site/SiteServiceImpl.java
index e7b6f7d262..16b622b4d7 100644
--- a/source/java/org/alfresco/repo/site/SiteServiceImpl.java
+++ b/source/java/org/alfresco/repo/site/SiteServiceImpl.java
@@ -1210,26 +1210,22 @@ public class SiteServiceImpl extends AbstractLifecycleBean implements SiteServic
     {
         final int maxResults = size > 0 ? size : 1000;
         final Set<String> siteNames = new TreeSet<String>();
-        
-        // MNT-13198 - use the bridge table
-        String actualUserName = personService.getUserIdentifier(userName);
-        if(actualUserName != null)
-        {
-            Set<String> containingAuthorities = authorityService.getContainingAuthorities(AuthorityType.GROUP, actualUserName, false);
-            for(String authority : containingAuthorities)
+        authorityService.getContainingAuthoritiesInZone(AuthorityType.GROUP, userName, AuthorityService.ZONE_APP_SHARE, new AuthorityFilter(){
+            @Override
+            public boolean includeAuthority(String authority)
             {
                 if (siteNames.size() < maxResults)
                 {
                     String siteName = resolveSite(authority);
                     // MNT-10836 fix, after MNT-10109 we should also check site existence
-                    // A simple exists check would be better than getting the site properties etc - profiling suggests x2 faster
-                    if ((siteName != null) && hasSite(siteName))
+                    if (siteName == null || getSite(siteName) == null)
                     {
-                        siteNames.add(siteName);
+                        return false;
                     }
+                    return siteNames.add(siteName);
                 }
-            }
-        }
+                return false;
+            }}, maxResults);
         if (siteNames.isEmpty())
         {
             return Collections.emptyList();