Error trying to apply 5.2.1 update

It sounds like the update isn't properly updating the files. Can you check that the /administrator/components/com_jfbconnect directory is properly writeable?

If so, please try disabling the JFBCSystem, JFBConnect Authentication, JFBC User and JFBC Content before you perform the upgrade. Then, when you install, check if there is are different error messages displayed (that may have been hidden by that error above).

After that, go to the JFBConnect -> Configuration area and see if that loads.

If all goes well there, start re-enabling the plugins.

The cause of the failure is that something is trying to load a file that was removed in v5.2.x. That file is no longer used or needed, and nothing should be trying to load it anymore. We'll need to narrow down what wasn't upgraded properly or what change has been made on your site that's still trying to load the old file.

I hope that helps,
Alex

Michael,
I honestly have no clue why that works. Our installer actually disables and re-enables the plugins during the upgrade process, so it shouldn't have been necessary. Either way, what matters is that it works!

Glad we could help get you going. As always, should you have any other questions or need more help, just let us know.

Finally, if you haven't already, please consider leaving a rating and review for JFBConnect, or our support, on the Joomla Extension Directory. It certainly isn't required, but is very appreciated:
extensions.joomla.org/extensions/social-...ook-integration/7215

Thanks,
Alex