Well, I know that this is an old post, but I was just now able to fix this problem for myself, so I thought I will leave a comment here.
When I tried to backup my data today, deja-dup almost completed the backup but finally during verification gave an error, saying that the data is corrupted and backup must be deleted. In retrospect, I remembered that I had a failed network connection while backing-up the last time and may be that could be the source of error.
So here is what I did, and it seems to have worked:
- Using Nautilus I navigated to the network location where I backup my data. (File -> connect to server...)
- Made the hidden files visible. (View -> show hidden files)
- Changed the view to list (View -> List)
- Sorted the files based on modification date, latest files first.
- Finally I deleted the recent files (today's date + previous date)
- Then I tried to backup again and it seemed to have worked.
Just to test it, I deleted few files and tried to restore them, and it has worked fine. A more rigorous test may be required. I will do that later and update my findings.