To change single digits to recognized double digits in Excel, you can follow these steps:

1. Select the column that contains the single digit numbers.
2. Right-click on the selected column and choose "Format Cells" from the drop-down menu.
3. In the "Format Cells" dialog box, select the "Custom" category.
4. In the "Type" field, enter
   Code:

   "00"

   (without the quotes) as the format code. This will add a leading zero to any single digit number in the column.
5. Click "OK" to apply the formatting to the column.

Now, when you enter a single digit number in the column, it will automatically be displayed as a double digit number with a leading zero. When you click on the cell, it will still display the leading zero. This should resolve the issue you were having with entering the data into Access without errors.