Instead of a live SQL Server database, you can specify a snapshot file. The database snapshot is a proprietary file, created by the schema compare, that contains all the information necessary to recreate the structure of a database.
A snapshot file can be specified for the source or the target database. However, the database that you intend to synchronize, has to be a live database. The synchronization script cannot be executed in a database created from a snapshot file.
Below is the xml fragment that creates the database from a snapshot file:
<LeftDatabase><LoadFromSnapshotFile>D:\QA\Idera\SqlSchema\Snapshots\AdventureWorks.snpx</LoadFromSnapshotFile></LeftDatabase><RightDatabase><SqlServer>DEVSRV003\SQL2019</SqlServer> <DatabaseName>AdventureWorks</DatabaseName><TrustedConnection>true</TrustedConnection></RightDatabase>