Export Method - Do you know how to export the solution if you don’t have the original installer or source code? (optional)

(Not recommended) In unusual cases where you don’t have source code (for your own customizations) or the setup files (from 3rd party vendor) of the SharePoint solutions that have been deployed in the SharePoint 2007 server, there is a way to export the solution files.

1. Download Solution Exporter from Mark Wagner's Cogitation Blog and run it on the SharePoint 2007 server. This allows you to export the installed solutions from the source SharePoint server.
2. Export all of the solutions out of the SharePoint farm.
3. Copy the C:\SharePointCustomizations folder to the destination SharePoint 2010 server.