Solution for PKS Failed to load exclusion information: Invalid formula syntax This error can occur when the Regional options on the client machine are not compatible with WinNonlin. Try opening Regional Options and make sure that the List separator is set to s semicolon “;” and not a comma “,” then try to load the scenario again. If the problem persists, open Tools | Options | Workbooks tab in WinNonlin, and uncheck the ‘Show Formulas’ checkbox. Then, try to load the scenario again.