email attachments

Are you right-clicking on the name of the attachment as it appears under the body of the email? Perhaps it appears twice?

Using the right-click method or the drop-down icon on the right side of the message (save all) yields the same result: Select the directory and click save. No errors, no saved files.

The Save as in the drop-down menu refers to the email itself, not the attachment. Describe what you do to the name of the attachment below the body of the email.

First image: email footer

Second image: right-click, drop down, save all. I have been using this method for years. Wouldn't save.

Third image: expanded attachments. Unable to save from here as well. Drag and drop from here to explorer was the only thing that worked.

Sorry. Have you uninstalled and reinstalled Thujnderbird?

No. That shouldn't be necessary. It only happens with one sender. (Of course that would be my most active client...)

Is that sender sending attachments in an odd format, or somehow locked?

If you look at image #3 that I posted, you will notice the first file "body_part_0.html". This is generated when the email is composed (MS Windows / Outlook). It started occurring when we were trying to solve the "winmail.dat" problem. This was done almost exactly three (3) years ago (Oct 2020). It solved the "winmail.dat" problem but the attachment issue just started happening yesterday.

Wow, I think you're completely out of my league. Have you asked your correspondent if anything changed for them yesterday?

He and I will discuss it later. Thanks for your consistent attempts to provide answers. Definitely appreciated.

The problem may be that TB doesn't find the correct MIME type for certain attachments like .dwg. You might have better results with this add-on:

https://addons.thunderbird.net/en-US/thunderbird/addon/openattachmentbyextension/