Hi Vincent, Error number 0 in 11: Uncaught exception com.xpn.xwiki.XWikiException: Error number 0 in 11: Uncaught exception at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:317) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:129) at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProces sor.java:425) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449) at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:121) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at org.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.j ava:126) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:66) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFi lter(SavedRequestRestorerFilter.java:208) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFi lter(SetCharacterEncodingFilter.java:111) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja va:222) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja va:123) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase .java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171 ) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100 ) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java :118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Proce ssor.java:1041) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(Abstrac tProtocol.java:603) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java: 310) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:11 45) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:6 15) at java.lang.Thread.run(Thread.java:744) Caused by: java.lang.IllegalArgumentException: An Entity Reference name cannot be null or empty at org.xwiki.model.reference.EntityReference.setName(EntityReference.java:183) at org.xwiki.model.reference.EntityReference.<init>(EntityReference.java:151) at org.xwiki.model.reference.DocumentReference.<init>(DocumentReference.java:15 6) at org.xwiki.model.reference.DocumentReference.<init>(DocumentReference.java:89 ) at com.xpn.xwiki.user.impl.xwiki.XWikiAuthServiceImpl.findUser(XWikiAuthService Impl.java:458) at com.xpn.xwiki.user.impl.sso.SSOAuthServiceImpl.createUserIfNeeded(SSOAuthSer viceImpl.java:269) at com.xpn.xwiki.user.impl.sso.SSOAuthServiceImpl.checkAuth(SSOAuthServiceImpl. java:115) at com.xpn.xwiki.XWiki.checkAuth(XWiki.java:3555) at org.xwiki.security.authorization.internal.XWikiCachingRightService.getCurren tUser(XWikiCachingRightService.java:229) at org.xwiki.security.authorization.internal.XWikiCachingRightService.checkAcce ss(XWikiCachingRightService.java:306) at com.xpn.xwiki.XWiki.checkAccess(XWiki.java:3568) at com.xpn.xwiki.XWiki.prepareDocuments(XWiki.java:4579) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:242) ... 41 more I want to prevent these kind of pages from being displayed to users.