Once a solution has been added to SharePoint, then there's no apparent way to download it. Using the SharePoint object model we can easily download a wsp using the 'SaveAs' method.
The C# code below illustrates how to download all of the solutions in the farm with just a few lines.
SPSolutionCollection solutionCollection = SPFarm.Local.Solutions;
foreach (SPSolution solution in solutionCollection)
SPPersistedFile wsp = solution.SolutionFile;
private void SaveWSP(SPPersistedFile wsp)
if (wsp != null)
string fileName = Path.Combine(