Opening HTML attachments in Mail

Occasionally, people send me evidential email chains as HTML documents attached to email messages. I find that if I double-click the attachment in the email, I get an error from Safari:


but if I drag the attachment to my desktop (or anywhere else, for that matter) and double-click it in Finder, Safari can open it without difficulty.

If I double-click attachments of any other kind (docx, pdf, jpeg) they’re opened in the appropriate app, as would be expected.

It doesn’t matter much, but I’m curious. Any idea why what’s going on?

You say that docx, pdf, jpeg are not affected, but could it be this problem?

Possibly - but I’m using Monterey and the issue exclusively affects .html documents.

What happens if you use Save Attachments under the File menu to your Desktop and then click on one of the files. You could choose get info to specify what should open it. That might handle for email attachments also.

The issue isn’t that the wrong application is invoked. As I wrote, double-clicking an HTML attachment in Mail activates Safari, but Safari then says it can’t open it.

Of course I can save the document, yes, in a variety of ways (such as dragging it to the desktop), and it then opens without trouble when double-clicked. It’s that workaround that I use.

I’m just puzzled that double-clicking in Mail doesn’t work and that this only happens for HTML attachments.