How can I delete Rapid boards in Jira 8.5.8 that are restricted and not visible to admins?

[Adidas AG]

Boards have been created by externals who have left the company.

The boards are not findable even with Admin rights.

Is there a way to access the boards and their filters ?

[Alexis Robert]

Hi @Adidas AG , 

the ability to change a board owner (and thus recover boards from inactive users) has been added from version 8.11 : https://confluence.atlassian.com/jirasoftware/jira-software-8-11-x-release-notes-1013852753.html#JiraSoftware8.11.xreleasenotes-filters

For ealier versions, you could try using a free addon called "User Switcher" that will let you login as another user, and then change its board ownership : https://marketplace.atlassian.com/apps/1211740/user-switcher-for-jira?hosting=server&tab=overview

Let me know if this helps, 

--Alexis