I just tried to update a non-mame database from a dat file. The database was placed in a subfolder of \RomCenter\romcenter\datas\ (i.e. \RomCenter\romcenter\datas\TestDB). While updating, RC asked for the new name of the database. I left the default (which wasn't the same as the existing one) and pressed "update". The new database however was not created under \RomCenter\romcenter\datas\TestDB as i expected but instead it was placed under \RomCenter\romcenter\datas. IMO it would be better if it was placed in the same location as the original database.