The recommended way to migrate the DS-Client application and its internal databases in one shot is to use the dsclient & dsdelta database recovery procedure, orphaned backup sets recovery should be used only when there are no backups of dsclient & dsdelta databases from the old DS-Client.

If the dsclient & dsdelta database files location is different on the new DS-Client machine (this would be the case if a newer version of SQL Server is deployed on the new DS-Client machine and the SQL installation path is the default one both on the old and new DS-Client computers), the loading of the dumps must be done manually with SQL Management studio, so the steps would be in this case:
1. Install new SQL and new DS-Client on the new machine (same DS-Client number and encryption keys as the old one)

2. At a time when no backups are running on the old DS-Client, disable scheduled activities (DS-User > Setup > System Activities > Scheduled activities - disable)

3. run a daily admin manually on the old DS-Client (DS-User > Setup > System Activities, run daily admin)

4. once the daily admin completes, go to Start > Administrative Tools > Services, and stop the DS-Client service, set it also to 'Manual" so that it does not start when that machine is restarted.

5. recover dsclient & dsdelta databases on the new DS-Client (DS-User > Setup > System Activities > repair DS-Client database > recover DS-Client & dsdelta databases), this process will save the database dumps in the DS-Client buffer path, default C:\Windows\Temp
When prompted to restart the DS-Client service, just stop it, do not restart.

6. restore using sql management studio the dump files available under the DS-Client buffer path ( restore first the full dump dsclient.dmp, in the restore wizard under "options" tab choose the option 'leave database non-operational and do not roll back uncommitted transactions" and "overwrite existing database" after the restore completes restore the the differential dump dsclient_diff.dmp, in the restore wizard under "options" tab choose the option "leave the database ready to use". Repeat the procedure for dsdelta.dmp and dsdelta_diff.dmp.

If you used SQL Express edition on the old DS-Client and had some expand databases on the old DS-Client computer (e.g. expand0001, expand0002, etc., this can be seen in DS-User > Help > About DS-User > DS-Client info), these databases must be created first in SQL Management studio, then restored from the dsclient database dumps (same step, first the full, then the differential).