Synchronize with any source not working properly (no replies)

Configuration

Client:
Windows XP SP3
Mysql Workbench 6.1.7.11891 build 1788

Servers:
Developing & testing:
Windows Server 2008 R2 Core
MySql Server 5.6.19

Production data hosting:
Windows Storage Server 2012 Standard
MySql Server 5.6.19

In MySQL WB I created a model of the DB I need to manage.

When I use the function "Synchronize with any source" to align the test db to the model, everything works fine.

When I use the same function to align the production db to the model, the target schema is reported as if it's empty (the screen "Differences found" reports N/A for each table).

For this reason the synchronization process fails, because the target schema is NOT empty and contains most of the tables of the model but the SQL scripts generated for the alignment of each table don't do anything because they begin with "CREATE TABLE IF NOT EXIST".

I created a new schema in the production DB and synchronized it twice with the same model.
The first time (target schema empty) everything worked fine.
The second time it didn't, because the target schema was reported empty and it wasn't.

Thanks to anyone who will help.