Q: problem opening file after numbers 4.0 update

Hi to all!

I have a problem with the new version of Numbers, 4.0, updated on my MacBook Pro (mid 2012 with Sierra10.12) on 27/09/2016:

I have a Numbers file into my iCloud folder, a file with 7 tabs, plenty of tables and counts, which I create every year (this is an account book). I updated the file for the last time on 26/09/2016, in the morning, and it worked perfectly with both the MacPro, the iPhone and the iPad. After the update of the App on the Mac, when I try to open the file I obtain "It is not possible to open the ### file for an unknown reason. To open the file restore a previous version" (I don't know the exact message since I'm translating from the italian version, forgive my imprecision). The error is the same both on Mac, iPhone, iPad and iCloud online.

If I try to restore a previous version, there is no way to recover the file.

The very strange issue is that I have the same problem also with the 2015 version of this file, which is saved on my Mac (and NOT on iCloud), but not with the 2014 version.

How can i solve this issue?

Or do I have to cry, having lost all my data of the last 9 months?

Thanks for any comment!

A.

p.s. the dimension of the file is consistent with the content