How to Decode Email Attachments

By Andrew Schrader

If running either a Windows or Mac operating system, your computer comes with its own "zip file" decoding program (like "WinZip" for Windows or "RAR Expander" for a Mac). These will decompress most file attachments, but not all. If you have a file extension your computer cannot handle, you will need to download another program (see Resource 1 or 2).

Things You'll Need

  • "WinZip" (Windows) or
  • "RAR Expander" (Mac) or
  • "Stuffit Expander" (Windows or Mac)

Decoding Email Attachments

Step 1

Download, setup and install an "Expander" (see Resource 1 or 2) if your computer does not already have one. Now you can open (or "unzip") your attachment files.

Step 2

Right-click on the attachment icon below your email heading. Scroll down and click on "Open With." Choose your compression program.

Step 3

At the pop-up screen, choose whether you'd like to "Open" or "Save" your downloaded files.Your "decoding" or "compression" software should automatically choose a program to open your file with, once it is "expanded." If not, you may have a file that your computer is not compatible with (see Warnings 2).

Tips & Warnings

  • Check the file extension on your attachment, which will tell you more about what program to best open the file. For example, an attachment with a file extension of ".jpg" indicates that it is a picture, which can be opened in several programs, depending on your needs.
  • Avoid opening attachments on "junk" or "spam" email.
  • Macs cannot open ".exe" files. These are Windows specific.