>>>At home on a machine with VFP 5.0a ,local data, I build an '.app' file. When I issue a 'SET STEP ON' I get a "FEATURE NOT AVAILABLE" error.
>>>
>>>However, at work with VFP5.0a installed , local data and using an '.app' file I issue 'SET STEP ON' and it activates the debugger with no problems.
>>>
>>>Why no errors at work? but errors on home machine?
>>>is it some kind of environment setting i am missing?
>>>Any Ideas?
>>
>>Are you running the Developers version of VFP at home?
>i am using the developer's edition at home
>> If you're only running the Runtime, you don't have access to the debugger.
>i have access to the debugger when i use SET STEP ON from something not compiled into an '.app' file
>
>In addition I build the '.app' at home, thus, the entire project is also present at home.

Hmm, Ed mentioned another cause of that particular error message. It sure sounds like you've got the right stuff at home. How are you trying to start the APP, from Explorer, or from inside VFP with DO YOURAPP? If you're trying to do it from Explorer, it loads the runtime, not the developers version to actually run the APP.