Outlookで開くとPDFがエラーとなり開けない

Hi 繁津,

We're sorry for the trouble you had, would you mind sharing more details about the issue? Are you on a Mac or Windows machine and what is the version?

What is the version of Adobe Reader installed? To identify, refer to Identify the product and its version for Acrobat and Reader DC

What happens when you double click the PDF file attached in the Outlook email?

What happens when you single click on the PDF file which is attached in the Outlook email? Do you get the option of Preview as shown in the screenshot?

What is the version of Outlook installed? try updating Outlook to the latest version available and check.

Also, check for any pending updates of Adobe Reader from help>check for updates and reboot the machine after installing the updates.

You may also refer and try the suggestion from the following Adobe discussion Over all

Try changing the file association once and check. How File Associations Work - Windows applications | Microsoft Docs

Also, follow the instruction of deployment of Adobe Reader on virtual machines VIRTUALIZED DEPLOYMENTS — Enterprise Administration Guide

Technical support boundaries for virtualized or server-based environments

Feel free to update this discussion for any further assistance.

Thanks,

Anand Sri.