EXEs run in the default FoxPro SET environment, your development system runs in a SET enviroment that you define with Tools/Options settings, your config.fpw.

You probably have a difference between the setting of EXACT between your runtime and devtime environment.

Your main prg should set the environment to the precise state that you want it to be. Remember that private data session forms run with the VFP default settings for each SET, see the help topic SET DATASESSION for more information.

>In a form, I have the formula to check a field X of a table --- if X = "" ...
>It works fine when I run the form in VFP. But it has wrong operant error after I complie it to an exe file.
>Finally I change it to if empty(X) ... then it works fine in both VFP and in its exe file. Does it mean we should use the empty() instead of = "" if we want to check empty field?