In previous versions of Excel when you had a drop-down list that contained duplicates those duplicates would show up in the drop-down list. This has been fixed in the latest versions of Excel. The duplicates are now removed.

In the image below the list of fruit in column A has duplicates.

When we use this list as the source for our drop-down list Excel will remove the duplicates and only show the unique entries.

In cell D1 press in sequence Alt D L (don’t hold the keys down) this opens the Data Validation dialog.

In the Allow drop-down select List. In the Source box select the range A2 to A10 on the sheet and click OK. See image below.

When you click the drop down in cell D1 you can see that the duplicates have been removed.

Excel has been making progressive improvement recently. This is another example of those small, behind the scenes improvements.