Did any one faced this issue while installing Magic Mover for Notes And Attachments to Lightning Experience package.
You missed configuration steps prior installation
From installation guide:
Before installing the AppExchange package, the Set Audit Fields upon Record Creation org permission is required. When we migrate attachments and files, we set system field values like Created Date, Created By, Last Modified Date, and Last Modified By. These fields are considered audit fields.
Note: If this permission isn’t enabled before you install the tool, installation fails.
From Setup, enter User Interface in the Quick Find box, then select User Interface.
Check Enable “Set Audit Fields upon Record Creation” and “Update Records with Inactive Owners”.
Also you have to follow more steps after installing the package. See the installation guide (scroll to Customization Guides)