Support

Do not trust the broken and untrustworthy information in the so-called “Pre-update check”. Its logic is completely broken. It tries to use the extension update information to determine if a version of an extension is compatible with the new version of Joomla. This is idiotic, and I have told the Joomla! maintainers four times between August 2020 and July 2021 (the year prior to the Joomla 4.0 stable release).

Extension developers will of course choose to not make available an older version of their extension to a newer Joomla version. We do not want people installing Akeeba Backup 8 on Joomla 4, even though technically it is compatible. The reason is that it does not and cannot have full support for some Joomla 4 features which are not present in Joomla 3. Joomla shows that in the “pre-update check” as Akeeba Backup 8 not being compatible with Joomla 4 which is, not to put too fine a point on it, utter bollocks and completely against our official migration guide. Do note that the latest version of Akeeba Backup 8 includes a system plugin which hijacks the results of the “pre-update check” to restore the truth about our software. We shouldn't have to do that. Joomla MUST NOT give false information to its users and spread FUD about third party software. What they are doing is class action lawsuit material. I have warned them.

It would further seem that the uninstallation didn't fully work and you are left with entries in the #__schemas table about Akeeba Backup which further mislead Joomla's utterly broken extensions installer code to treat this as an update, instead of a clean installation. Hence the error message you receive. When I tried reporting this and other major problems with the Joomla extensions installer and updater I was treated like rubbish, they personally attacked my professional capacity and integrity, and when I submitted a Code of Conduct violation form I was laughed at and blocked from contributing to Joomla because I "cause drama". Well, if reporting real issues and asking to not be slandered for that is "drama", sure, I do. If the Joomla maintainers don't want to interact with their community they should just take the project private and let the community fork it into something that is actually community-led, not just in theory. As a side note, all other major extension developers have long stopped contributing to Joomla exactly because of this toxic behaviour from the project's leadership. Now the Joomla maintainers are on their own. They made their bed, they have to sleep in it. But I digress.

The first thing you can try in your case is to completely uninstall and reinstall Akeeba Backup. Please remember that you need to uninstall the Akeeba Backup package extension, not the component.

If this doesn't help, uninstall Akeeba Backup once more. Then look in your #__extensions table. Is there a row with element = com_akeeba? If so, note down the extension_id for that row. Then open the #__schemas table. Find the row in that table that has the same extension_id you noted before and delete it. This will finally let Joomla do a clean install of Akeeba Backup.

Yeah, something looks to have been VERY stuck in your database or your filesystem. The usual suspects are phantom records in #__extensions or #__schema, with a very plausible runner-up being a leftover package manifest file in administrator/manifests.

This could all be solved if Joomla had advanced options in the installer interface, one of them being “Treat this as a fresh installation” which would tell Joomla's code to nuke the extension folders before writing files into them, and run the extension's installation SQL files (instead of the update SQL files). Of course, that's a very pragmatic approach to the messy state real-world sites end up in. If you were to try to explain that to Joomla maintainers who only understand ideal conditions in a lab environment they will not “get it”. If they don't “get it” they will not allow it to be implemented, even if there are willing bodies to do the work.

This is where my frustration stems from. In the past, us 3PDs were Joomla's “reality check”, its grounding. We offer support to our clients, we see how nonsensically messy real sites can get, we figure out why stuff breaks, and how to fix them. We were allowed to offer our insight as issued, code fixes, and entire features. Over the past decade, we were pushed aside. Demoting issues talking about more generic stuff to "discussions" and making the RFC process opaque and impenetrable from outsiders has led Joomla to become an echo chamber for its so-called leadership. This is a dangerous position for any organisation to find itself in.

The only light at the end of this tunnel is that there are people in the organisation who are trying to undo the lasting damage of the project's restructuring in 2015. Why, yes! The echo chamber Joomla leadership has found itself in was caused by that restructuring. I had explicitly warned them about what would happen before (https://www.dionysopoulos.me/refactoring-joomla.html) and towards the conclusion (https://www.dionysopoulos.me/the-problem-is-the-vision.html) of the restructuring. I didn't fall from the sky, I was a business consultant for Christ's sake! I saw all the red flags of dysfunctional organisations in the proposed structure. Hence this this comment of mine, made 9 years ago, reads today as eerily prescient.