Today we had a power shortage and I lost my work in Process Manager. I was sure the diagrams are automatically saved.
Process Manager creates a draft during your work so if something interrupt it, you will be able to restore it, when you open the process again. It works only if the first revision of the model was saved, otherwise your work will be lost.
KBA , BPI-SIG-PM-MOD-EDT , Graphical Editor for SAP Signavio Process Manager , How To