Autosave not working

Never ever ever trust a computer ... just ... don't!

I've been on them for over 30 years now, and every way they can screw you over, they will at some point.

So do not rely on any application's autosave function! 

In Premierre, for professional sanity and safety, in stand-alone project workflows, you should:

• Do routine save-as to an iterative name, and continue in the iterated project;
• Do routine save-a-copy to another drive, and probably, have that set to be backed up online;
• check that the online backup of the saved copies is actuall getting a usable project file on the cloud service you use.

As someone who's been through a number of nasty failures, I cannot stress the above enough.

This happens occasionally so it's always a good idea to check to make sure autosave is working.  Sometimes creating a new project and the importing the old project may solve the problem and resetting preferences as Ann suggests can also be helpful.  

Here's the way I set my system up.  I save my project to a folder on my startup drive.  The folder is automatically backed up to dropbox.  Because I pay a reasonable monthly fee to dropbox (there's a discount offered with the adobe creative cloud subscriptio) I can access all versions of a file saved in the last month...  If you need any help setting this up in dropbox, let me know.  And then I put my autosave folder on my media drive.  So there's some reduncancy in my workflow.  

Might want to reset preferences.