@Renzo D'andrea - The only way to edit boards that reside in a Free Plan team is to be a team member. So, quite often people sign up for a free Miro account, invite people to edit boards with them, and these new editors/team members start creating boards in said team.

You will need to delete these users. To see who they are, I would suggest switching to list view:

Now you can see the owner:

Then go to the users page:

And then remove/delete them from the team: https://help.miro.com/hc/en-us/articles/360017571234-Remove-users

You will then be prompted to take ownership of their boards and can delete their boards, therefore making yours editable again.

Another trick to quickly work on a VIEW-ONLY board is to duplicate it and work on the newly created board (just remember to delete the older ones). This works because the 3 most recently created boards in a Free Plan are editable.

Deeply appreciate your message and reply. Sadly I did all of this and these are boards to push me to take upgrade plan. 

Their name does not exist in my list. 

The only way to get rid of them was to move into another team boards. 

This is very disappointing from a privacy perspective.

Miro does not add random boards to a team in order to push them to upgrade. If you have the “Team Admin” role in that team, you can delete all users and all boards.

The Team Admin role can delete all users in the team at which point they will be the owner of all boards in the team and can delete them.

I believe you.

But two questions:

1 - why those boards did not have the option to delete them?

2 - Why could not find their name in the team board list or any email address associated to them?

There was any other way whatsever to delete those boards. I am on a free plan, Team Admin and there was no other options. 

@Renzo D'andrea - I sent you a private message. You should see it by going to your forum inbox → https://community.miro.com/inbox/overview