Now that Office 2019 is released there is a new feature that IT admins (and general office staff) should know about; Auto-save.
Auto-save is a feature that saves a document every few seconds so that you don’t have to. Here’s the catch, it only gets enabled when the document lives in OneDrive, OneDrive for Business, or SharePoint Online. The purpose of this feature is to prevent loss of data and to enable real-time document collaboration between users. The impact of these new features means that you may have to change up your workflows when dealing with documents that live in O365.
What if / document testing: If you have ever opened a file with no intention of saving it, so that you could model some changes or attempt something that you aren’t sure you want to save then keep reading! If you are opening a document that lives in O365 (aka has auto-saving enabled) you will need to make a copy of the document before making changes.
Make Changes then Save As: If you open files, change them, then save them as a different document as part of your routine then you will need to change up that workflow and make a new copy of the document prior to making your modifications.
Excel Views: If you have an auto-save excel file with pivot charts and other graphs and tables, any modifications you make to the the views of these graphs and charts will be auto-saved.
Here is more information on how to deal with auto-save as an IT administrator, along with configuration options on the document itself. https://support.office.com/en-us/article/what-it-administrators-should-know-about-autosave-88e0f80f-e5ea-441b-9c5a-259f08490ae7?ui=en-US&rs=en-US&ad=US