The seed file name or the location want to change.
In the Product.cfg (edit via Notepad), located in DriveName:\Program Files (x86)\Bentley\ProStructures V8i S8\ProStructures\config\appl
one can find the entries for that, like MS_SEEDFILES and MS_DESIGNSEED.
Here you can change the name via MS_DESIGNSEED and the location via MS_SEEDFILES.