>After compiling into exe some method code disappear. It is frequently happen with command buttons click event code. But not only these type of objects can "produce" this strange behaviour.
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Do you have old copies of your classes or classes with the same names as those in your project somewhere else on the network? It is very easy for VFP to build the wrong or incompatible components in to your project. The discription/path panel at the bottom of the project manager will show the path of your forms and class libs. Also check the ClassLibrary property of each class.

Every time I open a backup of a form or a class I rename the directory it is in so VFP cannot remember the location.

If that does not whork then something is corrupted, your PC, the VFP install, your project or a class.