The calendar database must not be corrupted. Use the csdb check command to check your calendar database, and if necessary, run the csdb rebuild command to rebuild the database. For information about these commands, Appendix D, Calendar Server Command-Line Utilities Reference.
You must have sufficient disk space for the new destination target database and if applicable, your backup database.
To run csmig, log in as icsuser (or as the Calendar Server runtime user ID specified during configuration). If you run csmig as superuser (root), you might need to reset the permissions for the migrated files.
You must also have privileges to manage the attributes of calendar users in the LDAP directory server that stores user preferences.
Calendar Server must be stopped.