You can use the Output Level setting to control the amount of output LINGO generates.  There are four settings available:

Verbose—Causes LINGO to display the maximum amount of output, including full solution reports.
Terse—Less output than Verbose, with full solution reports suppressed.  This is a good output level if you tend to solve large models.  LINGO also suppresses Export Summary Reports generated when exporting data to spreadsheets or databases.
Errors Only—All output is suppressed, with the exception of error messages.
Nothing—LINGO suppresses all output.  This level may be useful when taking advantage of the programming capabilities in LINGO, in which case, you will add statements to your model to generate all required output. Keep in mind all output is suppressed in this mode, meaning that error messages are also not displayed. Therefore, the Nothing output level should only be used once a model has been thoroughly debugged.

The default is for LINGO to be in verbose mode.