Do one of the following:

Find all cells with data validation  

1. On the Home tab, in the Editing group, click the arrow next to Find & Select, and then click Go To Special.

   

2. Click Data Validation, and then click All.

Find cells that match certain data validation settings  

1. Click a cell that has the data validation settings for which you want to find matches.
2. On the Home tab, in the Editing group, click the arrow next to Find & Select, and then click Go To Special.

   

3. Click Data Validation, and then click Same.

An Excel table may be linked to a SharePoint site   You cannot remove data validation from an Excel table that is linked to a SharePoint site. To remove data validation, you must unlink the Excel table or convert the Excel table to a range.

You may be currently entering data   The Data Validation command is not available on the Data tab while you are entering data in a cell. To finish entering, press ENTER or ESC.

The worksheet might be protected or shared   You cannot change data validation settings if your workbook is shared or protected. For more information about how to stop sharing, or to remove protection from a workbook, see Use a shared workbook to collaborate and Change or remove protection of worksheet or workbook elements.