AutoComplete will help you enter data by completing what you type, based on similar data in adjacent cells in the same column. If you enter the name John in a cell, and then type the letter J in the cell immediately below it, AutoComplete will fill in the letters ohn completing the word John. If you have two words with the same first letter in a column of adjacent cells, John and Jack for example, and you type a J, AutoComplete will wait until you type a second letter to discern the most likely match to complete the entry.

 

If you want to turn the AutoComplete feature off, click Tools in the menu bar, and select the Options menu item to display the Options dialogue box. (Tools->Options)

 

 

 Select the Edit tab and clear the Enable AutoComplete for cell values checkbox.