Non visible modules


Some modules presumably installed on my website do not appear in the module list. Actually the module may well absent but an error “module already installed” appears when trying to install it.

Steps to reproduce

No so clear from scratch, but on site test-rcc-drupal8, the module views slideshow has the problem. It does not appear in the list of modules and any attempt to install it from leads to " Views Slideshow is already installed" error.

Possible fixes

I bet that uninstalling and reinstalling the module would cleanup the situation, but uninstalling from the configurations pages is impossible as the module does not appear in the list.

Hello Sebastien,

According to the error, the module is already installed so trying to install it again throws the error you mention.

Did you try to search for the module and enable it like the GIF below?


Hi Konstantinos,

the problem is precisely that when you search the module, it’s not there ! Also not there if you try to search it for uninstalling it.

The problem has disappeared after a cloning to the site. So if you ever experience it, just create another site, clone to it and clone back.

The source is probably a bug in the drupal migration code between drupal7 and drupal 8