Re: [xwiki-users] BUG: Attachments become empty after a while

This is almost definitely caused by the attachment not saving properly. Despite the failure to save, the cache holds the attachment for a time but eventually it is cleared and the attachment appears to vanish. The cache inconsistency is fixed as of 2.5M1. As far as the attachment not saving properly and showing no sign, usually we start by blaming mysql max_packet_size. If you upload an attachment about the size of the largest attachment you ahve uploaded so far, check the tomcat log and you will probably see an exception trace. This will tell you what caused the problem.