In response to your query, if you have dell data safe online backup the local backup is not required, in general local backup is to back up data to an external device which is a disc & online backup is the space provided to back up data online.
Please find below the link’s which explain you more about the difference between data safe online & local back up.
1. Data safe online:
2. Data safe local:
Please let us know if this helps.
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Dell Social Media Responder