Jozef,

It sounds like you might have a dangling object ref that is holding up your app. If you open the data session window do you see any dangling data sessions in the cbo?

does a

CLEAR ALL
CLOSE ALL

allow you to rebuild?

You may need to spend some time in the debugger stepping through your app shutdown code.

>I am sure that the app file is opened because fopen("myprog.app",1) return -1
>and I can not delete the file by myself also. I hope that mistake is on my side but I do not see the reason. I use all display command option and it seems that my app object is destroyed in proper way, debuger trace and locals windows are blank and I can work in VFP normally untill I want to build the app file again. Simply it seems that VFP8 can not close the file without any information what is the reason.