I have a brand new installation of Joomla 3.6.5 and VM 3.0.18 .
I try to make it multi language.
The site works fine... But VM has problem with it.
I try to add a product or a category in Greek (default language and I see the flag over the VM menu in the left). I choose save and know it should have the option to make the text in english. I choose the English language from the menu in the left but nothing happens (it dosn't add the english flag near the texts that I should change in english). I choose Greek again and the Greek flag now appears. I rechoose english but the Greek flag is still there. And every change I make is in Greek.
If I choose save, sometimes it saves it in Greek and sometimes in English... Only by accident I manage to save the correct text in Greek and in English...
I have check and the file media/mod_languages/images/en_gb.gif is in the correct place, but as it seems the problem is not because of the image, but because the menu that should change the languages is not working...
I have in Joomla and in VM activate both languages.
I think all of this is solved in 3.0.19, directlink http://dev.virtuemart.net/attachments/download/1046/com_virtuemart.3.0.19_extract_first.zip