I tried to update to Joomla 4, but failed. So I restored to the previous version on server. But after the restoration, although the website (www.mslmaster.com) looks fine, but the Joomla itself does not.

Almost all of the menus on the control panel give this error message.

Class 'JFormFieldList' not found

enter image description here

Any solutions?

  • 1
    Did you restore to an empty folder or copies files back over the top of what was there for Joomla 4? If you switch on Error Messages to Development in Global Config, configuration.php, via your control panel file manager you should see more details about where the issue is occurring.
    – Irata
    Jul 19 at 7:37
  • I restored to system backup. After a few hours trying to figure out the problem, I eventually asked the tech guy to delete everything and install again. Joomla finally went back to 3.10. Jul 19 at 11:15
  • Good to hear you got it working again. If you copy your reply into the Answer Box below then you will be able to mark this issue as resolved.
    – Irata
    Jul 19 at 12:08

1 Answer 1


This issue was resolved after hours of anxiety. The solution was to delete everything and re-install all the files.

Not the best solution, because we don’t know what went wrong during the update, as after the preliminary check, Joomla gave no serious warnings. And the site only had two plugins in total, and none of them was a problem.

However, the update to Joomla 4.1.x remains an issue. Perhaps Joomla can alway support Joomla 3.10? That will be really nice!

  • Do you have a separate environment where you can install Joomla 4 copy of your site and test it to find the problem(s) without affecting your running or live Joomla3 instance?
    – Irata
    Jul 19 at 23:51
  • May I ask which specific extensions the project had installed? @Xue
    – mickmackusa
    Jul 20 at 0:20
  • I don’t have a separate environment. But that sounds a good idea! Thank you. There are no specific extensions that I am aware of. Jul 20 at 0:50

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