How to discourage screen capture and encourage users to copy a message instead?

When encountering an error message, some of our end-users have a tendency to take a screenshot, crop it and copy-paste it in a word document or a pdf, and then they mail us that PDF...

This is typically quite cumbersome and we lose the context, messages get truncated, text is blurred by compression, etc.

However, all they have to do would be to hit Ctrl+C or click the prominent "Copy to clipboard" button to have a text version, which can just be pasted into anything, and which is just much easier for support and debugging (we have the exact and full error text, version numbers, etc.). We also have a "send mail" button and a "save report to file", which are almost never used. We already have a big fat notice in the error message dialog which says to prefer the above methods to screenshots.

But no, they still use the screenshot or snipping tool, and proceed to PDF'it. Sometimes they go as far as printing the screen and scanning the print to make a PDF (you can tell from the scanner artefacts...).

One key constraint we have is that the application runs in corporate networks, with no way to upload directly to a cloud server internet.

Usually, when you explain the simpler way, they will use the copy-paste text option... though after a few months, they forget about it and revert to the PDF routine, which seems to be standard modus operandi for issues with all their other software.

Any UX ideas ?