[ SOLVED] Categories and sub-categories disappeared

[domechan]

Hello everyone, I hope someone can give me some help.

I recently migrated to 1.7.6.7 from 1.6, everything ok after the various settings and configurations, the shop goes.
Today I try to add new products but I notice that in BO I no longer see some categories which, however, I saw very well after the migration and settings.
In the front everything works, the categories are there and also the sub-categories, the products go but in BO different categories and sub-categories have disappeared.

I go into the database and I see that the category_shop table is missing the categories, the ones I see are the ones it shows in BO.
So I go to the category table and see them all. All categories are associated with the same shop id, (1 in my case).

What happened? Anyone have any idea how to fix this?

I don't know if it was a module or not that created the problem but in fact now I have this problem.
Thanks to anyone who can give me some advice.

CAUSE AND SOLUTION 

I understood what caused the problem, a few weeks ago I had the problem that after the migration the name of the site owner had changed to "Owner"
therefore, following a procedure found online, I activated the multi-store function to change the name from the multi-store menu that was activated but unfortunately I did not notice that there was an option on the categories to be dedicated to the multi-store and then deactivating the multi-store deleted those categories not previously associated.

Fixed with a database query which copied missing categories from category to category_shop while keeping `id_category`,` id_shop`, `position`

Edited August 29, 2020 by domechan (see edit history)