You are using mySites.guru. This is a problem caused by their extensions update code. It applies the Download ID to all Akeeba extensions, including FOF which does not need one and MUST NOT have one.
The root cause for that problem is that unlike our Professional versions, the Core versions of our software and our software which does not have a Professional release (like FOF) are downloaded directly from our CDN hosted on Amazon CloudFront. Downloads from Amazon CloudFront do not include a Content-Disposition header. As a result, Joomla uses the request to construct a download filename. When a download ID is not present (as designed and as it happens WITHOUT using mySites.guru) this filename is something like files_fof-4.x.y.zip. The extension of that file is .zip and Joomla can extract it. When there is a download ID the request URL ends in &dlid=SOMETHING therefore the filename Joomla constructs is files_fof-4.x.y.zip_dlid_SOMETHING. The file extension now becomes zip_dlid_SOMETHING and Joomla reports that it cannot extract it since it stupidly uses the file extension to determine how to extract a file instead of inspecting the file contents.
Moving our free extensions to be delivered from our web server is impractical. We have several hundreds of thousands of downloads every month. Doing that would make our site unresponsive, even if we maxed out the capacity of our server at a massive cost (thousands of Euros per month). Using a CDN for these downloads is much cheaper (in the order of a few hundred Euros per month). Given that we do not allow you to enter a Download ID for the free of charge extensions we can live with the tradeoff. When SOMEONE ELSE, however, messes up with our software's update sites like mySites.guru did in this case things break. It's really not our fault. We have no control over what third party code can do to our software's update sites.
We had a suspicion this was the case ever since the first two reported cases last week. Today we were given access to an affected site and confirmed that this is caused by the mySites.guru extensions update code. We notified mySites.guru about this issue a few hours ago but they have not replied yet. We are waiting for a reply from them before making an official announcement on our site on Monday.
Meanwhile, there is a simple but annoying, manual workaround.
- Go to Extensions, Update, Update Sites.
- Find the FOF update site and delete it.
- Download the latest FOF 4 version from our site and install it on your site.
This restores the FOF update site to its normal state.
Please note that the error might recur since the mySites.guru code will try to modify the update site again. It is up to them to fix their code and undo the problem their code has created on your sites.
Nicholas K. Dionysopoulos
Lead Developer and Director
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