Each domain can be saved to the Common Warehouse Metadata (CWM) repository with any name you like. The Save and Save As options are available from both the Pentaho Metadata Editor File menu and the toolbar. Each time a domain is saved to the repository, a recovery export file of the domain is saved to the file system, under the .pentaho-meta directory. This directory is typically located in the your home directory. The recovery file contains the last successfully saved state of the domain. The files are named recovery_[studio:domainname].xmi.
You can restore a domain to the last saved state by importing the recovery file importing the recovery file from the file system. Domain restoration may be necessary because you want to revert to the last known good state of your domain in the event of repository errors or corruption.