Why is attachment not working in Outlook?

If you're on a computer, you might have the same problem on an older Mac. When the file is corrupted, the only way to solve it is to clear the cache memory on your Outlook. If this doesn't work, check the permissions on your emails. Some of the most common types of Outlook email attachments issued are encrypted and incompatible. If this is the case, you can clean the caches to ensure that your files can open properly.

See also - https://emailspedia.com/unable-to-open-outlook-attachments/