Exporting an investigation from Maltego Search adds all the returned data, including the main search and all subsequent searches, to a single Maltego graph.
You can only open a Maltego graph using the Maltego Graph (Desktop) Client.
If you purchased Maltego Search as a standalone product, you could open the Maltego graph using the free Maltego CaseFile or Maltego Community Edition (CE).
Alternatively, you can share the exported results of your investigation with OSINT experts who use Maltego Graph. This will provide them with an easy way to see and understand what you have discovered in your Maltego Search search should you need them to dig deeper into the investigation.