Word 2016

How many more times does this have to be said? THERE IS NO AUTOSAVE in Word.

There is an autosave of RECOVERY INFORMATION in the event of a crash, which may help recover documents in progress if Word crashes. System updates do not crash Word, they close it down without saving unsaved documents.

If you worked for 15 hours without once saving the document, frankly you are your own worst enemy.  You should save often. If you can't remember to do that - see http://www.gmayor.com/automatically_backup.htm 

As for the updates, you can configure Windows not to update automatically, but to do so at a time of your choosing.

You may be able to find some usable information in the Word recovery folder in the form of ASD files.

How many more times does this have to be said? THERE IS NO AUTOSAVE in Word.

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Whatever caused the tragedy, I believe Mr. Mayor's advice above is incorrect and his solution inadvisable.

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Mr. Mayor's information is correct and his advice is sound. The Add-In is free, people can choose to contribute for its production if they want. If you rely on the autorecovery feature, you will be disappointed eventually.

Mr. Mayor's advice is based on decades of experience not only using Word but assisting others in their use of it. I have personally observed him assisting people with this problem at least since Word 97.

Backup Copies enabled in Word options are a copy of a document when it is opened, edited and saved. One backup will be created of the pre-change document if this option is enabled.

AutoRecover is separate and may or may not kick in.

Here is a description from the

"AutoRecover and Backup Copies
"Hate losing work? I do. That's why I keep a very short leash on AutoRecover. I also tell Word to always make a backup copy. At this point in my life I have more disk space than I have time to re-create lost work.

'To set the AutoRecover interval, choose File > Options and click the Save tab. Under 'Save AutoRecover information every,' choose an interval that reflects your work habits. If you're a fast worker you might want to set it to as little as every minute or two. For most users the default 10 minutes seems a bit too infrequent. Note, however, that AutoRecover is not the same thing as automatic save. AutoRecover comes to the rescue only if Word crashes or you otherwise forget to save something. It does not automatically do a normal save of your document. Saving your document is up to you.
"To enable backup copies, select File> Options and click the Advanced tab. Under Save, enable Always Create Backup Copy.
"Even with both of these settings enabled, I still do frequent saves - every time I press the enter key and certainly every time the phone rings. It's extremely frustrating to see Word crash while you're on the telephone. I have been known to utter some rather colorful comments on such occasions."