You need to run it separately on existing documents. It doesn't work dynamically with the Office software, either. It works with Firefox (2nd bullet) but it does not integrate or work dynamically with the Office software.The 3rd product is a standalone desktop program - not an add-in - that is available for Mac (1st bullet).
Saving your files frequently is the best way to preserve your work.About your question “Autosave has reverted to 10 minutes (the default) - shouldn't the setting I input months ago 'stick' and not be changed by AutoUpdate?”Normally, updating Office shouldn’t change the settings which you set.I suggest you change the auto save time first. Hi Roaming,About “And not only that, how often the 'Autoreover' file is often useless or non-existent.”To prevent the data lost, we suggest you save the file to OneDrive, as it will auto save the file when you edit the file.Note: Do not use AutoSave and AutoRecover as a substitute for regularly saving your files by clickingSave. Microsoft office autosave file location.
Microsoft do NOT say that Office 2016 won’t be supported on High Sierra. They say: “During the beta period for macOS 10.13 High Sierra, no formal support is available for this Office.
By Mike Wuerthele
Tuesday, June 13, 2017, 09:21 am PT (12:21 pm ET)
Jan 27, 2018 Microsoft Office Home and Student 2019 provides classic Office apps and email for families and small students using one Mac. Buy online now at apple.com. Global Nav Open Menu Global. Office 2019 for Mac requires macOS Sierra, macOS High Sierra, or later, Windows 10, Windows Server 2019. (Is Microsoft Office Home and Student 2019. Jun 27, 2018 Even Office 2011 for Mac Home and Business continues to work fine for mw with the latest High Sierra 10.13.5. It is a 32 bit app so eventually it may stop working because of that, but Office 2016 for Mac is 64 bit so should work fine and the future Office 2019 for Mac would be 64 bit and should work fine as well.