>Hi,
>
>If you have an index order set for the table you are using and you change the value of that field, it might cause the problem you are having.

And the solution for that case (if the key really must be changed) is

seek cKeyValue
calc min(recno()), max(recno()) to nMinRcn, nMaxRcn;
   while KeyExp=cKeyValue
nOrder=TagNo()
set order to 0
go nMinRcn
scan next nMaxRcn-nMinRcn+1 for KeyExp=cKeyValue
   {processing happens here}
endscan
set order to (nOrder)

Worked flawlessly since FP2.0.