Jozef,

Like Jim, if I have have problems writing the DLL or EXE that it will throw a specific error about not being able to write the file, it doesn't just hang.

If you have errors in the code that is preventing your app from unloading from memory you need to fix those. Your hung application will prevent VFP from being able to read classlibs procedure files etc.

Can you do a build after a reboot, start VFP and then just build before ever running your application?

>I created quite new project file. Behaviour is the same.
>In meantime I found more direct reason of this hanging. VFP8 hangs while "buid app ..." command because old app file is still open so it can not be deleted.
>I tried different clear and close commands to close the app file - without results. Simply after several starting and ending cycles of my application VFP does not close the app file. Sometimes this happens after first exit from my application sometimes after "n" exit.