So, Outlook is asking to save your original e-mail every time you reply or forward.
There is an add-in that causes this issue, it is call the Outlook Social Connector 2016.
Not everyone is seeing an issue with it, so if it isn’t causing an issue, leave it alone.
If you ARE having issues, do the following:
Click the File TAB at the top of Outlook
Then Click Options near the bottom of the page
Now Choose Add-ins, then click the Go button at the bottom of the page
From the Add-ins page, un-check the Outlook Social connector 2016, you may have to scroll down to find it.
Once un-checked, click OK on every page until you are out of the options panel. Close Outlook and then re-open it.
This problem should now be fixed.