Post a pic of the bottom of the mouse.

for the serial number :)

here it is, sorry I have forgot about bottom pic :D

It’s fake, that’s why it’s not detected by Synapse.

Really? Bought it out of emag.ro the most trusted provider =))

emag is just a selling platform, where other users could sell their products. I’d return it and get it from some other viable source.

Look, I even have a photo of other unit with the same serial number (originally it doesn’t happen, because serial number is unique).

Yes, it is fake. Found a lot of other pictures on the internet with the same s/n.

On a forum, it was even mentioned that it is actually a “replica”.

Meh. 

Yup.

They’re using original serial number, that’s why it was telling it’s already registered. Still the mouse is a cheap fake, so I’d return it and get from official distributor or at Razer.com