Save It First
There are a few things you need to understand for Auto Save to be enabled. First, you have to have saved the document at least once! Auto Save only works if the document has been saved into a supported location. If you haven’t done that, there’s nothing to save; it only exists in the computer memory and has not yet been committed to a file.
Supported locations are anywhere in OneDrive or SharePoint. You can save any new document directly into either of these locations from the File > Save option.
If you have the OneDrive App signed in on your PC you can also save the file to your computer to one of the synced locations. The Desktop, Documents and Pictures folders are by default included in your synced locations, as well as the OneDrive account folders.
Once the document has been saved once, you can continue working on it and it will automatically save everything you do thereafter. This happens in the background. By default, all Office documents saved into a supported location have Auto Save turned on.
It’s perhaps easier to think of it as a sync, rather than a save. Everything you type or add gets synced to the central file in the OneDrive or SharePoint location. This sync is what also allows you to collaborate in real time with other people on the same document. Everyone is reading from the same synced central file held in Microsoft 365, not the copy saved to your PC.
Versions and Roll Back
Another advantage of Auto Save is you get a version history of your documents. Whilst you are saving as you go, every time you close the document, a version is created. That means that you can roll back at any time to a previous version. A new version is also saved approximately every 10 minutes while editing.
If you need to go back to an earlier version, just click Version History and select the one you need. You can also even compare them side by side to see what changed between the different versions.
Prevent Unwanted Changes
There are many reasons why you might not want changes to a document to be saved automatically. You might be using a template, have a draft copy that you need to markup changes instead of actual edits, or many other reasons.
Luckily it’s easy to turn it off. Just flip the toggle at the top of the window when you open the file.
However, you need to remember to do this right away. For a more fool-proof method, you can lock changes under File > Info > Protect Document and choose the first option – ‘Always open read only’
This is great for templates or any other document where you have a version you don’t want to be accidentally edited. When opened, you’re prompted that it’s marked as Read Only, but you can choose ‘No’ to open it for editing.
If you have a final version, you can also set it as such from File > Info > Protect Document again, choosing the final option. Again, this gives a prompt when opened, but you can still then click ‘Edit Anyway’ and continue making changes.
Make It Work For You
This is not an exhaustive list of everything you can do with saving, versioning, or preventing changes to documents, but it does hopefully give a useful insight into what options you have. For the most part, the Auto Save function is extremely helpful, and most people working on a document would rather have changes saved than not.
If you do need to prevent unwanted changes, setting it as Read Only is probably the easiest option, but find what works best for you and explore the other options available.
One final note, though, is on encrypting the document with a password. This may sound tempting and another way to prevent unwanted changes, but it’s something you want to avoid (see our article Why you shouldn’t password protect your Office documents) because it can have unintended consequences, not least of all locking yourself (and everyone else) out of it completely if you forget the password!
For more details on the Auto Save function, see this Microsoft Doc.