When you login to your IDrive account for the first time on a new Synology machine, it allows you to restore your previous computer's backup archive on your new computer. You can select the 'Adopt/Link to an existing location/computer' option for this. By adopting the previous computer's backup archive, you can avoid time consuming initial backup of your files in case you are replacing an old computer.
To adopt your backup archive,
Install Synology backup app in your NAS machine and login to Synology Backup App.
Click Adopt/Link to an existing location/computer when prompted to select location/computer for backup. A list of locations/computers linked to your account appears.
Select the desired computer/location from the list and click Adopt/Link Selected Location to restore your previous backups.
In case you do not wish to adopt your previous backups on the new machine, you can click Proceed to create new location with this computer name when prompted to select location/computer for backup.
Note: This feature is only available for certain accounts.