Forum Discussion
Default Office theme uses Times New Roman everywhere, not Calibri
What helped in my case was deleting default templates in "%USERPROFILE%\AppData\Roaming\Microsoft\Templates" changing the default language to "English US" or similar in Office 2016 Language Preferences, followed by opening Word and Outlook (to re-create default templates). I had "English Europe" set as default editing language, Office installation picked-it up from regional settings. This seems to have caused the Office to fall back to "Times New Roman".
What helped in my case was deleting default templates in "%USERPROFILE%\AppData\Roaming\Microsoft\Templates" changing the default language to "English US" or similar in Office 2016 Language Preferences, followed by opening Word and Outlook (to re-create default templates). I had "English Europe" set as default editing language, Office installation picked-it up from regional settings. This seems to have caused the Office to fall back to "Times New Roman".
For anyone else arriving here, I had the same issue and this solution almost worked for me, but not quite. In addition, I had to reset the Windows 10 default language (Settings -> Time and Language -> Region & language) back to "English US", in addition to the steps outlined below.
Only then the font in Outlook and Word would stop flipping back to Times New Roman and stay Calibri in my case.