>Thanks a lot. That is very clear.
>
>>The value returned by SYS(2015) is based on the system clock. It'll be unique on one PC but the same value maybe generated on different PC's. Download Convert SYS(2015) value back File #9704 to see details.

Sergey gave you the correct explanation.
I have used a routine to avoid this problem for many years. It was originally by Pat Adams (and that is going back to the DOS days).
I have it now in my oUtility class that I instantiate early in the program.

It basically returns the following:

Return Substr(Sys(3),4,4) + Substr(Sys(2015),7,4)

You can customize it by prepending letters, or maybe the current user initials or workstation name, or whatever.

HTH