Why am I unable to open an e-mail attachment?

Updated: 08/31/2020 by Computer Hope
E-mail attachment

Below is a listing of all the different reasons why you may be unable to open an e-mail attachment.


This page is for people who cannot open an e-mail attachment. If the attachment is missing or not available, see: Why can't I receive any e-mail attachments?

Unrecognized file format

One of the most common reasons why you can't open an e-mail attachment is because your computer doesn't have the necessary program installed to recognize the file format. For example, if someone is sending you a .PSD image file and you don't have Adobe Photoshop or another program that supports it, the file format cannot be opened.

In this situation, we recommend you have the sender save the file as a different format that the computer supports and re-send the attachment. If you are going to be working with this file format often, install a program or viewer on the computer that supports the file format. Below is a listing of some of the more common file formats send over e-mail, their file extension, and the programs used to open those files.

File type Extension Description
Document .doc or .docx Microsoft Word documents and can be opened with Microsoft Word, OpenOffice Writer, or Google Docs.
PDF .pdf Adobe PDF file that is opened with Adobe Acrobat or PDF reader.
Spreadsheet .xls or .xlsx Microsoft Excel spreadsheet that can be opened with Microsoft Excel, OpenOffice Calc, or Google Sheets.
Basic Image .gif, .jpg, .jpeg, .png These basic image formats are widely used and can be opened and viewed by every image editor or viewer.
Compressed file .zip, .rar, .z A compressed file that must be uncompressed before the files contained in the file can be viewed.
Bitmap .bmp Windows bitmap image that is primarily opened in Microsoft Paint and can be opened with many but not all image editors.
Movie .avi, .mov, .wmv, .mp4, .mpeg Movie files that require a compatible media player program to play.
Audio .mp3 MP3 audio file.
Executable .exe, .com An executable file that starts the installation of a program. Be cautious of any executable sent through e-mail as this is the primary method of distributing viruses through e-mail.
HTML .html, .htm HTML file. For example, a web page may be sent as an attachment in e-mail.

Bad file association or problem with program

Adobe Acrobat PDF icon

If the file format is something your computer should be able to open, but it's not opening correctly, its file format may be associated with the wrong program. Or, the program it's associated with may be experiencing errors, or was removed. For information about how to view and change file associations, see: How to associate a file with a program in Windows.

For example, let's say you want to view a PDF document. Many modern web browsers offer their PDF viewer, but this PDF is an attachment sent in an e-mail from a trusted sender. However, you don't have a PDF viewer, like Adobe Acrobat, installed.

Instead of trying to open the attachment directly from your e-mail client, save the attachment to your computer (e.g., save it to your desktop). Then, right-click the file and under Open with, choose a different program to open the file. If this works and you want the program to always open this type of file, right-click the file and under Open with, choose another app. Check the box Always use this app to open and select the program you want to use and click Ok.

Compressed file

compressed files

When needing to send multiple files over e-mail, it's not uncommon to compress all the files into a single compressed file and attach that compressed file to the e-mail. If the file is a .zip, .rar, or another compressed file format, it must be uncompressed before it can be opened.

Antivirus program preventing

If you have an antivirus protection program installed on your computer, make sure it is not causing problems with your attachments by temporarily disabling your antivirus.

Sender has an Apple computer and you have a PC

If the e-mail sender uses a Mac computer, and their attached files were not saved in a Windows-compatible format, you may be unable to open the attachment. Make sure the sender of the e-mail knows you're using Windows if they are sending you an attachment.

Outlook add-ins

If you are using Microsoft Outlook and unable to open attachments, make sure an add-in is not causing the problem. You can disable all add-ins in Outlook by following the steps below.

  1. Open Microsoft Outlook.
  2. Click File, Options, and then Add-ins
  3. Under Manage, click COM Add-ins.
  4. Click the GO button next to Manage, then uncheck all the add-ins.
  5. Once everything is disabled, click OK.
  6. Close Microsoft Outlook, then re-open Outlook to see if the issue is resolved.

Corrupt file

If none of the suggestions above helped determine or fix the problem, it is also possible that the attachment you received is corrupt. Reply to the e-mail asking the sender to verify the attachment works on their computer, and to create a new e-mail and attachment.