Board Thread:Support Requests - Getting Started/@comment-29455442-20190526100930/@comment-1038387-20190526113126

How "vanished"? Do you have the right url, or did you get a "Closed Wiki" message? If the latter, there should be a link that allows a database dump to be downloaded, for a limited time.

Sometimes small wiki are deleted after periods of inactivity, but to my knowledge that's wikis with less than 10 mainspace pages that are inactive for 6 months. Don't pin me down on those numbers, though.