MySQL Workbench: "Operation has completed with warnings"
The message is a bit unconcrete, so here's a translation: it appears when the statement 'SELECT @@lower_case_table_names' returns -1 or 0 (only for Win and OS X). So check, if case sensitivity is an issue for you.

Update:

The message you see is in fact only the title for a (potential) error dialog. The actual message is not listed in that small log. Look in the WB log (Help -> Show Log File) for the details.