Problem with attachment files

[mathieuf]

Hello,
I will try to explain clearly.
Sometimes I have got a problem when I receive attachment files in an e-mail.
For example an Excel file is encoded oddly. All the characters are transformed.
That works with Word file too.
The only solution I found is to "ZIP" the document but I can't ask my customers to do that.
Someone has a solution?
Thanks

[mathieuf]

Please Help me it's a very big problem...