Sorry, my fault: I misunderstood the part with the delete. You meant the rights, and not the 'delete' itself. But again to the rights hint: We double-checked the rights of the crucial sites, with different test-users and guests (without sessions). We testes in different browsers and even in VMs on different OS. I wrote even a small crawler to penetrate our site more regularly and controlled. We reproduced some guest-edits with our crawler. But we can't edit these sites when we are moving on our site as a guest manually. So we can't reproduce it directly and repeatable. We only know, edits and deletions are possible for (crawler-)guests sometimes under some unknown circumstances and causes, even if its not possible for 'us', when we are guests. I will test your extension 'Admin Tools Application' with CheckRights you posted on the reply later. Thanks! This will be very useful for our daily routine anyway. -- View this message in context: http://xwiki.475771.n2.nabble.com/severe-trouble-with-web-crawlers-tp7442162... Sent from the XWiki- Users mailing list archive at Nabble.com.