I upgraded from Office 2010 to 365 at the end of last year and am having a problem with Outlook that I can't seem to solve. I don't recall it doing this initially when I installed it last November on a Windows 7 PC but I switched to a new Windows 10 PC in December and that's when I first began to notice it. I have v1912.



If I reply to or forward an email, I (inconsistently) get the message:



The properties of this message "XXX" have been changed


Want to save your changes to this message?


If I click NO it does not show that I have replied to/forwarded the message. If I click YES it shows that I have replied to/forwarded it but removes at least part of the original message so I not longer have an intact version of the original email. I can retrieve this from the message I have sent or forwarded but I'd rather keep the original.



Outlook does not seem to do this consistently but I don't know enough about email formats to see if there's a difference between message types.


I can find reports of the pop-up message on the internet but those have not been helpful.


I have changes some setting in Options but that has not fixed the issue.