You can view file attachments in the Reading Pane or within the body of an email message without opening another program.
The attachment previewer feature in Outlook only works if you have the same version of Word, Excel, or PowerPoint installed as the version of Outlook being used to preview the attachment.
In the Reading Pane, click the attachment.
Switch between the attachment preview and the message text by clicking Message or the attachment.
Occasionally, attachments appear within the message body. The difference results from the message format.
Attachments within the message body can’t be previewed. To view these, open the attachment.
Outlook is on guard
To help protect you from malicious code when previewing files, Outlook disables embedded active content, such as scripts, macros, and ActiveX controls. Outlook also blocks potentially unsafe attachment file types (including .bat, .exe, .vbs, and .js files) that can contain viruses. Blocked attachment files can’t be viewed or opened.
It’s a good idea to preview or open attachments only from trustworthy sources. When you receive an attachment from someone you don’t know or that seems odd, contact the sender first.
Turn off attachment previewing
Outlook includes attachment previewers for other Microsoft Office programs. You can turn them off.
Click File > Options > Trust Center.
Under Microsoft Outlook Trust Center, click Trust Center Settings.
Click Attachment Handling.
To turn off the attachment previewers, do one of the following:
To turn off all attachment previewers, check the Turn off Attachment Preview box.
To turn off a specific attachment previewer, click the Attachment and Document Previewers box, and then check each previewer you want to turn off.