Never had this happen, what did I do other than NOT update.
Started new application this morning. BO's created, forms, queries, access levels and presentations done. Kept saving all throughout. Was saving a property on one of the presentations and Poof! The application reverted back to brand new. All Green, no objects, nada. I did not update or put under test so the DB is non existent. Just want to know where that hidden "Application reset to square one" button was to avoid in the future.