title: Background initialization failed. Stopping SonarQube
body: <p>I am updating the sonarqube (5.6.3 > 6.7.1) and the following error is occurring:</p>
  
  <pre><code>2018.02.01 20:37:21 ERROR web[][o.s.s.p.Platform] Background initialization failed. Stopping SonarQube
  java.lang.IllegalStateException: Unrecoverable indexation failures
          at org.sonar.server.es.IndexingListener$1.onFinish(IndexingListener.java:39)
          at org.sonar.server.es.BulkIndexer.stop(BulkIndexer.java:117)
          at org.sonar.server.issue.index.IssueIndexer.doIndex(IssueIndexer.java:247)
          at org.sonar.server.issue.index.IssueIndexer.indexOnStartup(IssueIndexer.java:95)
          at org.sonar.server.es.IndexerStartupTask.indexUninitializedTypes(IndexerStartupTask.java:68)
          at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
          at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
          at org.sonar.server.es.IndexerStartupTask.execute(IndexerStartupTask.java:55)
          at java.util.Optional.ifPresent(Optional.java:159)
          at org.sonar.server.platform.platformlevel.PlatformLevelStartup$1.doPrivileged(PlatformLevelStartup.java:84)
          at org.sonar.server.user.DoPrivileged.execute(DoPrivileged.java:45)
          at org.sonar.server.platform.platformlevel.PlatformLevelStartup.start(PlatformLevelStartup.java:80)
          at org.sonar.server.platform.Platform.executeStartupTasks(Platform.java:196)
          at org.sonar.server.platform.Platform.access$400(Platform.java:46)
          at org.sonar.server.platform.Platform$1.lambda$doRun$1(Platform.java:121)
          at org.sonar.server.platform.Platform$AutoStarterRunnable.runIfNotAborted(Platform.java:371)
          at org.sonar.server.platform.Platform$1.doRun(Platform.java:121)
          at org.sonar.server.platform.Platform$AutoStarterRunnable.run(Platform.java:355)
          at java.lang.Thread.run(Thread.java:745)
  2018.02.01 20:37:21 DEBUG web[][o.s.s.p.Platform] Background initialization of SonarQube done
  2018.02.01 20:37:22 INFO  web[][o.s.p.StopWatcher] Stopping process
  </code></pre>
  
  <p>We tried to delete the <em>/data/es5</em> folder, but with no result. Any idea?</p>