Hi
During my tests with NAV 2009 SP1 I ran into an old well known error / problem.
So why not write a post on it 
When starting a Navision Client (in this case a Classic Client) you may get the error “Yes is not an option” or a localize version “Ja is not an option”.
The Error can occur in a localized version, ex. DAN where you have changed your language to ENU and then closed the client. Next time when you wish to use the client, it will try using yes/no for authentification. This will not go well in a localized version.
The error can occur even if you don’t use shortcuts with parameters, because Navision unfortunately remembers your last choice and will try to open the database with a wrong language layer. It will not be solved be deleting the zup file or by adding an id parameter to your shortcut.
So – how do we solve the error? The only way is by adding the parameter ntauthentification to a shortcut. Then start Navision and afterwards change the language layer back or just leave the ntauthentification parameter on your shortcut
Example:
“C:\Program Files\Microsoft Dynamics NAV\60\Classic\finsql.exe” ntauthentication=1
Where 1 = Yes and 0 = No
