I have tested a fresh installation with the 2.3 WAR using: mysql Ver 14.12 Distrib 5.0.77, for redhat-linux-gnu (i386) using readline 5.1 using jetty-6.1.3 on: java version "1.6.0_12" Java(TM) SE Runtime Environment (build 1.6.0_12-b04) Java HotSpot(TM) Client VM (build 11.2-b01, mixed mode, sharing) I have not been able repeat your problem. On my installation, I was able to start with an empty database, start 2.3 and install the default XAR. I'm not sure what error you are seeing but there is an error which is "normal" for MySql It is: "Incorrect string value: '\xE9\x80\x99\xE6\x98\xAF...' for column" MySql doesn't support some of the characters used in XWiki translations. See: http://forums.mysql.com/read.php?103,359419,359419 Also you may see: "Caused by: java.sql.BatchUpdateException: Packet for query is too large" (The xar file may have become larger as of 2.3) In which case you have to increase the max allowed packet size. To answer your question about upgrading from 2.2 to 2.3, you can upgrade, XWiki was designed to allow that. Caleb Harald Kapper wrote: