[Toreth]

I've been editing a book and saving regularly when Windows decided to run an update. Of course the computer restarted and when I tried to open my book in Sigil, I got an error cannot load epub: C:\Users... When I showed the details I got the message cannot unzip epub: c:\users...

When I tried to open the book in Calibre's ebook viewer I get error: could not open ebook. not a zip file and the details showed:

calibre, version 2.20.0
ERROR: Could not open ebook: Not a ZIP file

Traceback (most recent call last):
File "site-packages\calibre\gui2\viewer\main.py", line 38, in run
File "threading.py", line 763, in run
File "site-packages\calibre\ebooks\oeb\iterator\book.py", line 99, in __enter__
File "site-packages\calibre\customize\conversion.py", line 241, in __call__
File "site-packages\calibre\ebooks\conversion\plugins\epub_in put.py", line 197, in convert
File "site-packages\calibre\utils\localunzip.py", line 223, in extractall
File "site-packages\calibre\utils\localunzip.py", line 210, in _extractall
ValueError: Not a ZIP file


The Nook app gave me the message: sorry unable to import.

I've even tried to restore my system but I still get the same messages. Is there any way to recover the file?

Thanks