The error message appears when the synchronize operation is started from the dialog, rather than from the Revit Synchronize button.
1. Create a local copy of the Central File in Revit 2016
2. Make some changes to the model
3. R-Exit Revit
4. Select “Synchronize with Central” in Revit message box
5. Select “ok” | You get the error message in Figure 1 above