Ravindra-

> IT SAYS 'FILE IS IN USE'. So now how do I know that file is already opened. Now suppose I will make use of USED() function.

You can tell by using the low level file function FOPEN(). Something like

lcDBF = "C:\SomePath\SomeDBF.DBF"
lnHandle = FOPEN(lcDBF, 11)

if lnHandle = -1 then it's in use. You'll need to FCLOSE the handle before you can use it. If the app is hitting data really hard then you *might* see the table used between the time you FCLOSE and then USE the file, but there would be strategies for manaaging that, too.