Make sure the list has a header, assume the list including header is
A1:A53160

in let's say H2 put

=COUNTIF($A$2:$A$53160,A2)=1


where A2 is the first cell with an order number


Now select A1:A53160, do datafilteradvanced filter, select copy to another
location and

put $I$1 there

in the criteria range put

$H$1:$H$2

H2 is where you put your formula


replace all cell references accordingly to fit your own data


then click OK



--
Regards,

Peo Sjoblom



"calibansfolly" wrote in message
ups.com...
I have a list of 53159 order numbers including dupes. There are
exactly three order numbers that only appear once. I need to track
down those three numbers. Any ideas?