Sorry for the strange title but it was the most appropriate description I could think of.
When I made some changes to allow GeoServer to connect to MS SQL Server then restarted the server it seems to have reset GeoServer's settings to something strange.
The admin password changed to something unknown to me (and it is hashed in the users.xml file).
The GeoServer now "belongs to The Ancient Geographers" and the administrator email changed to [email protected] (i.e. Ptolemy).
Has anyone come across this before? Even better does anyone know his password?