Finding Duplicate values within a single column

[Guest]

I have a list of e-mail addresses. I want to find all the duplicates. I have
sorted the list but the list is extremly long.
I have not found an effective method for doing this. I want the result to
show me where those duplicates occur.
Can anyone help me?
Thank you

 

[Guest]

I just realized that I posted this to the wrong group. i apologize. I will
re-post.
Thank you
Ed

 

[Harald Staff]

Hi

Select the column. Menu Data > Filter > Advanced filter, there's a "show
unique items only" checkbox.

It will not mark the duplicates, it will hide them, which I suspect may be
your goal. If not, or anyway, see Chip's page
http://www.cpearson.com/excel/duplicat.htm

HTH. Best wishes Harald