>>Yes, but SUS(2000) stops when find a file, Filer build a collection :-)
>>
>Right, but if we're doing it in the DO WHILE loop, should they be equavalent?

Only test will tell.
I have no folder with so many files in it to test.
But you could try:

m1 = DateTime()
oCollection = NEWOBJECT([Collection])
lcFileName = SYS(2000, [........])
DO WHILE NOT EMPTY(lcFileName)
   oCollection.Add(lcFileName,JUSTFNAME(lcFileName))
   lcFileName = SYS(2000, [........],1)
ENDDO
? DATETIME() - m1

*** Test fro Filer here