'Mail alerts' module not showing as installed

[D D]

Hello,

I have a module called ‘Mail alerts’ in my Prestashop 1.6 site. The module seems to be active (as it regularly sends emails to a specific email account). It also has its files and folders in my Prestashop installation in cPanel.

However, the module in question is not visible under 'Modules'. I tried to filter by ‘Installed modules’/‘Uninstalled modules’, ‘Enabled’/’Disabled’, but the ‘Mail alerts’ module doesn't show up. Instead, when I go to ‘Modules’ list and search for it, it shows as available for install.

The strangest thing is that I have a copy of the same Prestashop site (made with Softaculous on cPanel). The 'Mail alerts' module shows as installed on the copied site, but for some reason it's not showing on the original one. Any ideas?  

Edited March 13, 2018 by D D (see edit history)