Many friends like to use Excel for office work, but some friends still don’t understand the basic steps of Excel prompting duplicate items, so here the author has shared a tutorial on Excel prompting duplicate items, let’s take a look.

​ ​Select the range of the table to be set. Click [Data Validation] in the [Data] tab above. The higher version is called [Data Validation].

​​Set the permission inside to [Custom], and then enter =COUNTIF(A:A,A1)=1 in [Formula], which means starting from column A, starting from A1, all content can only appear once.

              Set the prompts given when data is duplicated in the error warning.

After clicking OK, the system will automatically give you a prompt next time you enter repeated content in the data column.

The above explains the basic steps of how to prompt duplicate items in Excel. I hope friends in need can learn it.