Hello Thomas, THanks for your help. That's the strange behaviour. Catalina log file came with lot of messages from solr (some indexing problems), but I do have on the browser only a blank page. I just changed the Xmx java tuning from 512 to 1024 (I though it was may be a memory error). But same behaviour : on launching a percentage on the browser from 12 to 50% and a blank page. Last Catalina : août 04, 2016 11:36:12 AM org.apache.catalina.startup.ClassLoaderFactory validateFile AVERTISSEMENT: Problem with directory [/usr/share/tomcat7/common/classes], exists: [false], isDirectory: [false], canRead: [false] août 04, 2016 11:36:12 AM org.apache.catalina.startup.ClassLoaderFactory validateFile AVERTISSEMENT: Problem with directory [/usr/share/tomcat7/common], exists: [false], isDirectory: [false], canRead: [false] août 04, 2016 11:36:12 AM org.apache.catalina.startup.ClassLoaderFactory validateFile AVERTISSEMENT: Problem with directory [/usr/share/tomcat7/server/classes], exists: [false], isDirectory: [false], canRead: [false] août 04, 2016 11:36:12 AM org.apache.catalina.startup.ClassLoaderFactory validateFile AVERTISSEMENT: Problem with directory [/usr/share/tomcat7/server], exists: [false], isDirectory: [false], canRead: [false] août 04, 2016 11:36:12 AM org.apache.catalina.startup.ClassLoaderFactory validateFile AVERTISSEMENT: Problem with directory [/usr/share/tomcat7/shared/classes], exists: [false], isDirectory: [false], canRead: [false] août 04, 2016 11:36:12 AM org.apache.catalina.startup.ClassLoaderFactory validateFile AVERTISSEMENT: Problem with directory [/usr/share/tomcat7/shared], exists: [false], isDirectory: [false], canRead: [false] août 04, 2016 11:36:12 AM org.apache.coyote.AbstractProtocol init INFOS: Initializing ProtocolHandler ["http-bio-8080"] août 04, 2016 11:36:12 AM org.apache.catalina.startup.Catalina load INFOS: Initialization processed in 720 ms août 04, 2016 11:36:12 AM org.apache.catalina.core.StandardService startInternal INFOS: Démarrage du service Catalina août 04, 2016 11:36:12 AM org.apache.catalina.core.StandardEngine startInternal INFOS: Starting Servlet Engine: Apache Tomcat/7.0.56 (Debian) août 04, 2016 11:36:12 AM org.apache.catalina.startup.HostConfig deployDescriptor INFOS: Déploiement du descripteur de configuration /etc/tomcat7/Catalina/localhost/xwiki.xml 2016-08-04 11:36:32,385 [localhost-startStop-1] WARN ltInstalledExtensionRepository - Invalid extension [org.xwiki.enterprise:xwiki-enterprise-ui-mainwiki-7.1.2] on namespace [wiki:xwiki] (InvalidExtensionException: No compatible extension is installed for dependency [org.xwiki.platform:xwiki-platform-chart-plugin-7.1.2]) 2016-08-04 11:36:32,403 [localhost-startStop-1] WARN ltInstalledExtensionRepository - Invalid extension [org.xwiki.contrib.forum:application-forum-ui-1.9.4] (InvalidExtensionException: No compatible extension is installed for dependency [org.xwiki.platform:xwiki-platform-ratings-api-6.4.4]) 2016-08-04 11:36:32,404 [localhost-startStop-1] WARN ltInstalledExtensionRepository - Invalid extension [org.xwiki.platform:xwiki-platform-search-lucene-ui-6.4.2] on namespace [wiki:xwiki] (InvalidExtensionException: No compatible extension is installed for dependency [org.xwiki.platform:xwiki-platform-search-lucene-api-6.4.2]) 2016-08-04 11:36:35,578 [localhost-startStop-1] INFO o.x.s.s.i.EmbeddedSolrInstance - Starting embedded Solr server... 2016-08-04 11:36:35,578 [localhost-startStop-1] INFO o.x.s.s.i.EmbeddedSolrInstance - Using Solr home directory: [/var/lib/xwiki/data/solr] 2016-08-04 11:36:39,896 [localhost-startStop-1] INFO o.x.s.s.i.EmbeddedSolrInstance - Started embedded Solr server. août 04, 2016 11:36:40 AM org.apache.catalina.session.StandardManager doLoad GRAVE: "ClassNotFoundException" lors du chargement de sessions persistantes: java.lang.ClassNotFoundException: org.xwiki.container.servlet.filters.SavedRequestManager$SavedRequest java.lang.ClassNotFoundException: org.xwiki.container.servlet.filters.SavedRequestManager$SavedRequest at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.Thread.run(Thread.java:745) août 04, 2016 11:36:40 AM org.apache.catalina.session.StandardManager startInternal GRAVE: Exception au chargement des sessions depuis le stockage persistant (persistent storage) java.lang.ClassNotFoundException: org.xwiki.container.servlet.filters.SavedRequestManager$SavedRequest at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.Thread.run(Thread.java:745) Cordialement Stéphane Lassire Courriel : [email protected] -----Message d'origine----- De : users [mailto:[email protected]] De la part de Thomas Mortagne Envoyé : jeudi 4 août 2016 11:03 À : XWiki Users Objet : Re: [xwiki-users] Xwiki on Debian 8 + Tomcat7 - GRAVE: "IOException It's the first time I see this error. Not even sure what a persistent session is. Maybe Tomcat is configured to stored the session on disk to get it back when restarting and something put a not serializable object (DefaultStringEntityReferenceResolver which is indeed not serializable) in it. Is XWiki running properly after that ? Even if it's indicated GRAVE it seems to me you just lost this part of the session but XWiki does not really expect the session to be serailized anyway so you should probably disable that if possible.