Thanks Ed, I'm currently in the process of trying firstinstance.prg.

Kev
>>Hi
>>
>>I need an app to only be run once at one time.
>>
>>What's the best way to detect if a VFP app is already running ?
>
>Look at my ClsEvent class, available for downloads from the Files Section - it includes an example of how to use it to force things to operate ingle instance, whether it's an app, a form, or whatever.