Installing Extension from 3.x on 4.0.4 Error 500 behavior::modal not found

[Christiano73]

Dear all,

I am new to Joomla. I have a running Installation Joomla 4.0.4.
I have tried to install an Extension that was made for 3.x.
During the installation the Error 500 behavior::modal is shown.

I guess this routine is new or obsolete in 4.0.4.
Any experience to resolve this error ?

Thanks for any hint or guidance
Christian

[AMurray]

I have tried to install an Extension that was made for 3.x.

Extensions designed for 3.x are not guaranteed to run in 4.0.

Installing extension

• It would have helped if you advised which extension you're trying to install.
• Joomla 4.x is only a couple of months old, extensions for what you want to do may not be available, yet.
• It's best to check the Extension Directory periodically as you might find a 4.0 version of your extension there eventually.
• Did you check to see if the extension had a Joomla 4.0 version?
• Did you read the installation instructions for that extension and note if it was 4.0 compatible or not?

Restoring site

My suggestions:

1. Restore from backup (backing up your site is clearly and strongly advised in the "Install Extensions screen).
2. Start over with a clean install of Joomla 4 if you haven't done too much work on the site.

[sozzled]

See viewtopic.php?f=808&t=989466