compare for duplicates

[Dave Rattigan]

I have an excel file with 7000 rows. Column B's alphanumeric values are 3 to 8 character lot#'s and column C's numeric values are 3 character associated suffix's. After sorting entire file by column B, I drag down this formula to tag all duplicate shop orders which is the combination of B's lot# and C's suffix:
=IF(AND(B2=B3,C2=C3),"duplicate","not duplicate")
This tags all duplicates EXCEPT the last duplicate. I then autofilter all the "TRUE" and then print that as my exception report. I need a macro that will loop and tag ALL duplicates. I've toy'd with some
A=[b2].value & [c2].value
and some "Do While A" statements but no luck yet. Then it would be nice if I could print to sheet2 but only the tags are really needed at this time.

[qball]

Iffin the last duplicate is the problem, change formula to look for dupes before and after. Something like the below;

=IF(AND(B2=B3,C2=C3)OR AND(B2=B1,C2=C1),"duplicate","not duplicate")

Then just filter on the dupe/not dupe column.