Can't open an attachment in Outlook by double-clicking it

Original KB number:   3106898

Symptoms

In Microsoft Outlook 2016, Outlook 2019, and Outlook for Microsoft 365, when you double-click an attachment to open it, the file does not open. However, you can right-click the attachment and then select Open to open it.

Cause

This issue may occur when the setting for the double-click speed for your mouse is too fast.

Resolution

Change the double-click speed setting to a slower setting:

  1. In Control Panel, select the Mouse item.

    If Mouse does not appear in Control Panel, type mouse in the search box, and then select Change mouse settings.

  2. On the Buttons tab, slide the Double-click speed slider to the left, and then select OK.

    Screenshot of the Button tab in Mouse Properties.

Note

Sliding the Double-click speed slider one step to the left is typically sufficient to fix this issue. However, if the issue still occurs, you may have to slide it further.