Autorecover is not working. Can I alter the path - and will this help?

I have studied previous questions on this topic - none of them really solve the problem.
I started using LibreOffice on 2015-11-03, v5.0.2.2 on Windows 8.1
So far it has crashed 10 times while using Writer and calc.
I have Tools>Options>Load/Save>General>Save set to autorecover every 3 minutes.
Not one single autorecover has been successful. Every one has failed. I have lost a lot of work.
My work is all kept in a Dropbox folder on drive D:. I have tried copying documents to a folder on Drive C: where the operating system sits and working on them from there but it doesn’t help.
I wonder if there is a problem with the path which LibreOffice wants to use for making autorecover copies?
The path on my machine seems to be C::\Users\myname\AppData\Roaming\LibreOffice\4\user\backup
Could I make a new place to store backups and reset the path - would this help?

The first step in most fixes is to Reset your profile (Q62646) (easily reversible).