Delete original and duplicate

Select Column-A>>Data Menu>>Data Tools>>Click Remove Duplicates>>Untick My Data Has headers>>Tick Column-A>>Click Ok

Hi and welcome to the forum

Try his...
1st, put this in B1 and copy down...
=COUNTIF($A$1:$A$3188,A1)
Then apply filters...Home tab/Editing/Sort and Filter/Filter
Uncheck 1...OK
delete what remains. If thats all you have, delete the row, not just the cell contents

You canthen either take filters off, or check 1

The previous suggestion will keep the first entries and delete the duplicated data.

The below formula will mark the duplicated records as delete and show the text Keep when it is present in a single time

In B2 Cell

=IF(COUNTIF(A:A,A1)>1,"Delete","Keep")

Drag it down..

Apply Auto filter for Column B and select Delete and delete the row

Hi Horgans and welcome to the forum,

I'd create a Helper Column and count how many of Col A are the same. Then I'd sort by this Helper Column to find the stuff you need.

See the attached.

all letters/all numbers/mixed letter and number...should not matter with that formula. It is counting duplicates, no matter what they are. check to see if you have training spaces?

Please do not upload a picture of your file...rather, upload a sample of your workbook, showing what data you are working with, a few samples of your expected outcome is (manually entered is ok) and how you arrived at that. (exclude sensitive info). Pictures are pretty much impossible to edit, and no-one wants to re-type your data for you Also, not all members can upload picture files (Company firewalls and stuff)

oops I meant traiLing, sorry These are extra spaces at the end of text in a cell. Just by looking at the contents, you may not necessarily see them, but if you edit the cell and look in the formula bar, you will see that the cursor is 1 or more spaces away from the end of the text
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This formula, copied down works just fine...
=COUNTIF($A$1:$A$3188,A1)

However, some of your data does indeed have trailing spaces. for example, look at the entries in A1187:A1189
A1187="F071"
A1188="F071 "
A1189="F071 "

1 way around this would be to create a helper column (I used C) and copy this down...
=TRIM(A1)
Then change the formula in B to this...
=COUNTIF($C$1:$C$3188,C1)

I have not seen the OP's file just posting the below formula base on the FDibbins post #12 text

=IF(TRIM(A1)="","",SUMPRODUCT(1*(TRIM($A$1:$A$3188)=TRIM(A1))))