If you have problems opening an email attachment, it might be due to the wrong or missing email header information.

1. Save the attachment in your local drive (e.g. D:\data).
2. Rename the file extension as “*.uue". (e.g. filename.uue).
3. Right click the file and choose "Open with WinZip".
   
4. Select the file “Unknown.001” and click the “Extract” button to extract the encoded file to the local drive (e.g. D:\data).
   
5. Rename the file “Unknown.001” using an appropriate file extension according to the file format (e.g. Unknown.doc for Word document) to get the decoded file.