Hi @bonily
Have you used many game mods before or just cc? A lot of 'plain' cc, doesn't need extracting as it's a package file to begin with. It sounds to me like you may have just 'clicked' to open or something like that, or your computer has 'chosen' the player to identify it since it's not something it's dealt with before.
With most game mod files, they're in a .rar (zipped) folder they need to be extracted first with an app like win rar and others, once you extract them (I checked the Mermaids mod) you'll find about 3 package files, which can then be put into your mods folder. If this is the problem; do a search for win rar download, it's free and once you have that installed when you right click on the mermaids.rar file you'll have an option to 'extract here', do that in a 'clear folder', then copy / move them to the mods folder.
Hope this helps, as I was wondering if you use many 'game mods' or ever needed the unzipping before as you say it 'happens a lot'?
Sasha
nb: If this solves your question, please mark the reply as having been the solution, so as to help others with a similar problem in the future. 🙂
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