You can remove leading, trailing, and extra spaces between characters and numbers in Excel using TRIM(), SUBSTITUTE() or Find and Replace.

Look for extra spaces in your values' cells. If your duplicate values have extra spaces in their cells, those spaces will also cause the Remove Duplicates tool to consider them to be unique values.

How to Remove Leading Blank Spaces in Excel. However carefully you monitor the data you enter and import into Microsoft Excel, and the output of formulas and functions that produce new values, it ...