The 'Operation Failed' Outlook attachment error message is a very common error that prevents Outlook users from opening attachments. This error is caused by the fact that older versions of the software don't work with some newer versions of Windows. The problem can also occur if a user is using an outdated version of the Outlook software or because the software has a problem with its internal components. Fortunately, there are a few solutions to this problem.

See also - https://emailspedia.com/cannot-attac...outlook-email/