I purchased User from Solspace and installed it. I then noticed the issue with the Modules tab. I uninstalled User and the problem was still there. This is the error I am getting.
Error
Unable to load the following language file:
/lang.index.php
I looked to see if lang.index.php was in the installation files from EE but I did not see one in there. I don’t know if this file needs to exist in the language -> english directory or if this is an internal error EE is generating. I am running 1.6.6 commercial version of EE.