What i would do:

1. Do a backup
2. Open in my database the table *_update_sites in phpMyAdmin
3. Delete the row

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What i would do:

1. Do a backup
2. Open in my database the table *_update_sites in phpMyAdmin
3. Delete the row

There is also a table update_sites_extensions which holds the cross references from update_sites to extensions. That should also be checked.

It is by design that you cannot delete a core update site, and the rebuild button also doesn’t touch core sites.

But maybe that should be changed/improved. I know of a few other cases where a site had a long update history and duplicate update sites for the core.

But maybe that should be changed/improved. I know of a few other cases where a site had a long update history and duplicate update sites for the core.

For non protected update sites such as joomla core a rebuild of the update sites should resolve any duplicates

For non protected update sites such as joomla core a rebuild of the update sites should resolve any duplicates

@brianteeman Reading the code here looks to me as if this is not the case: https://github.com/joomla/joomla-cms/blob/5.2-dev/administrator/components/com_installer/src/Model/UpdatesitesModel.php#L304-L331

Rebuild should delete all the update sites and then rebuild the table from the extension xml

Rebuild should delete all the update sites and then rebuild the table from the extension xml

@brianteeman I agree that it should do that, but it doesn't. Any update site which refers to the core (joomla files extension) will not be touched. I had once investigated a similar problem and tried it. Reading the code, especially the comment, made me then believe it is desired behaviour, so I haven't opened an issue.

I agree that it should do that, but it doesn't.

@brianteeman , I opened this issue because the “rebuild” button does not solve the problem of removing the update server double. My opinion today is that this is a bug that needs to be fixed. But maybe the development community will decide otherwise.

Rebuild should delete all the update sites and then rebuild the table from the extension xml

@brianteeman I agree that it should do that, but it doesn't. Any update site which refers to the core (joomla files extension) will not be touched.

Which is what I said

For non protected update sites such as joomla core a rebuild of the update sites should resolve any duplicates