New C/AL Editor in NAV 2016 is really fine. I think we were waiting it for the years. I’ve already posted about it here.

But if you want to use old C/AL Editor from any reason, it is a possible. I don’t know reasons for it, but if you want…

You need to run Development Environment from Command Prompt using finsql.exe command and adding useoldeditor parameter. First you have to navigate to your C:\Program Files (x86)\Microsoft Dynamics NAV\90\RoleTailored Client folder and then run this command. This useoldeditor parameter is one of the parameters you can use. Complete syntax is following:

finsql.exe [command=<command> | designobject=<object type> <object ID>,] [servername=<server>,] [database=<database>,] [collationname=<collation>,] [file=<file>,] [filter=<filter>], [importaction=<default|overwrite|skip|0|1|2>,] [langid=<ID>,] [logfile=<logfile>,] [navservername=<name>,] [navserverinstance=<instance>,] [navservermanagementport=<port>,] [ntauthentication=<yes|no|0|1>,] [objectcache=<cache>,] [password=<password>,] [temppath=<path>,] [tenant=<tenant ID>,] [username=<user name>,] [synchronizeschemachanges=<yes|no|force>, ] [useoldeditor=<yes|no>]

You just need to set useoldeditor=Yes or only useoldeditor. If you still want to use new editor from command prompt, you need to set useoldeditor=No.