microsoft excel courses in - Source from an external worksheet for Data Validation

Also if you have the source data in another workbook

Create a range name for the list of names on a worksheet in Workbook A e.g. external_names

Go to workbook B and worksheet where the data validation is to be set up.

Create a range name e.g. external_list
Then type in the Refers to: =workbookA.xls!external_names

Select the cells required for Data validation.
Select Data, Validation
Settings tab, Allow, choose List
Fill in source with =workbookA.xls!external_names

Fill in Input Message and Alert Message,
Click OK

The drop down list now uses the data from the external Workbook A.