I recently downloaded SolidWorks 2015 and when i build a new part and finish it, i save it in a specific file. close solid works and re-open it and nothing was saved except for the name of the file, although it shows exactly what i built for the first second once its loaded, as soon as its completely loaded it disappears, it wont even show any of the features in my feature tree.
Local folder or network? If you try it in other folders, same result?
You might try running a repair on SW or, if it's repeatable, contact your VAR.