If you create a download file which includes names or addresses containing diacritics (i.e. accents) then you may find that when you open the file in Excel that the diacritics are not properly displayed - however if you open the file in other programs - e.g. Notepad - then the diacritics are displayed properly.
To resolve this problem you can
On a computer running Windows
Open the CSV file using Notepad
Click 'File > Save As'
In the dialog window that appears - select ANSI from the Encoding field - as per the screen shot below- then click Save
Open this new CSV file using Excel and your accented characters should be displayed properly
On a Mac:
The options are:
if you have access to a Windows computer follow the method using Notepad above - Excel on the Mac will then display the diacritics properly
Use the Numbers application instead of Excel
If the options above are not possible then the best you can do using Excel on a Mac
Create a new spreadsheet
Import the data from the downloaded file using the Data menu by choosing Get External Data | Import text file - for the File origin setting choose Unicode 7 - this will remove the accents from the characters