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John D
John D, Bachelor's Degree
Category: Microsoft Office
Satisfied Customers: 9666
Experience:  Bachelor of Science - Engineering Consultant
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I have multiple email lists saved as csv. I have emailed a

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I have multiple email lists saved as csv. I have emailed a couple of these lists and I know each email on these lists are unique. Now I have another list which I am not sure if it contains duplicates of emails I already sent before. So what is the easiest way to filter out the ones I've emailed already from the ones I have not.



If by email you mean "email addresses", please put the two lists in the same workbook and attach the file here so I can setup the formulas for you


Customer: replied 4 years ago.
Great! How do I attach a file I don't see any options for that?

Ok go to and upload the file (no need to signup) then copy the "File ID" number (or the download link) that you will be given and paste it here in your reply.


If the file has sensitive information let me know before you upload it


Customer: replied 4 years ago.
Here is the link:

The list on the left are the people I have emailed. The list on the right is a new list which may or may not have duplicates. So I want the duplicates filtered out of the list on the right. Hope that makes sense.

Got it. So you want he duplicates to be removed from the shorter list on the right and not from the longer list on the left, correct?



Customer: replied 4 years ago.

Ok, uploading the file, one moment...


Ok here you go


Attachment: 2012-02-06_004830_fulllist.xls


The formulas in the yellow column returns X next to the email where a duplicate is found. After identifying all the duplicates I copied the data to the next sheet 'Final' and deleted those that have X's


Hope this is ok. Let me know if you have any questions, and thank you for clicking Accept if you are satisfied with the solution



Customer: replied 4 years ago.
Dude this is freaking awesome! I will accept of course. I will shoot you a small tip if you can explain the formula to me.


Sure, one moment please..



In cell D1 the formula




does the following


first, this part


looks in the range A1:A5437 for any occurrence of the email in cell C1


If found, that countif will count as 1. If not found it will return 0


So the entire formula is:

if the count is greater than 0 then put an "X", otherwise leave the cell in D blank


Hope this helps


Thanks in advance for accept and feedback (bonus would also be great)




Customer: replied 4 years ago.
One last question. For the final list on the second sheet, did you run another formula or manually go through and delete the ones with yellow X's?

Please go ahead and accept and pay bonus while I review your last question


Thank you




John D and 5 other Microsoft Office Specialists are ready to help you

Ok what I did was copy columns C and D and paste them on the second sheet using Paste Special > Values.


Then I sorted the list on column E so all the X's will be grouped together, then I deleted that group



John D and 5 other Microsoft Office Specialists are ready to help you