When installing component in Joomla! Extension manager, it can happen that the installation process will be not successfully finished. For example: component's size is too large and Joomla! Extension Manager is not able to install it fully. Mostly because of time issues. In such case, it happens that only some data of the component are installed in Joomla! database.
And that is problem because incomplete data items cause that:
- the installed component does not work properly
- and it cannot be reinstalled (because stored incomplete data prevent from it).
In such case, the best method to solve this issue is to remove the component from Joomla! manually and completely (see article: Removing component from Joomla! system manually) and install the component again. Be aware when removing the component from the system manually, all its data will be lost. But as mostly this problem happens during new installation, there are no data yet, so there should not be any problem to remove the component regarding losing data.
Of course if you have e.g. time or memory problems, such needs to be solved first - before new installation. You can test other installation method too, see article: How to install large components with help of FTP in Joomla!
What kind of error is displayed in such case? For example:
- missing menu item links to the component in administration menu
- 404 error message - component not found