Migrations will typically involve a user working on the migration processes while other users are continuing to work with content in the library. As a result of this overlap and the remapping actions, run the migration processes on a copy of the library rather than the production environment. The remapping actions involve updating the pathways used by objects to external files - from the locations used by your on-premises installation - to the locations used in Author-it Cloud. As a result, if changes were made to your production library before the migration, publishing and other actions using external files could be affected. For more considerations for planning a migration see Scheduling the migration.
Why we recommend using a copy of your library
Libraries and copies
SQL: create a backup of your library, then restore the backup and rename it. Use this copy of your library for your migration.
Jet: Localize automatically creates a copy of your library. The copy uses the library name (with the date and time of the migration appended to the name). For example, when Author-it Cloud Migration Toolkit is run on a library called Sample, the copy is called Sample_20130108094721.adl.