How to fix a persistent download issue

That Outlook prompt is commonly caused by a Windows internet security setting, not by the email itself.

Fix it in this order:

1. Close Outlook.
2. Open Internet Options.
3. Select the Advanced tab.
4. Under Security, clear Do not save encrypted pages to disk.
5. Select OK.
6. Start Outlook again and test the download.

If that option is already cleared, or it is grayed out, the setting is likely controlled by Group Policy. In that case, the system administrator needs to change it.

If the problem is specifically with pictures in HTML email showing a red X or failing to download, the same setting is the documented cause.

• HTTPS linked images in HTML emails display the red X
• How to get the pictures to download when settings are correct in Outlook Classic - Microsoft Q&A