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All software is licensed on a per computer basis. For example, if you wish to use SQL Backup on more than one computer you will need an additional license for each additional computer on which the software is downloaded and installed. Furthermore, this license is not transferable between computers and as such you may not transfer the software between computers without purchasing an additional license from Red Gate Software.

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Hard to believe you can't transfer a server-based license to another machine after decommissioning the original box (or losing it so a disaster, etc)!!