Hello everybody! My name is Cecilia and I've owned a Lenovo Vibe K5 for quite some time now. I've had this problem of dupplicate icons. The same thing as described here happened. I would install an app, then out of the blue it would dupplicate the app's icon for no reason (so I thought) and when I tried to uninstall the extra icon, I ended up uninstalling the entire app itself. Later I discovered it wasn't a virus or anything related to the store selling me a problematic phone. It is actually a bug related to the Lenovo laucher. Basically, when you transfer an app you installed in the internal memory of the phone, to the memory card you've put on your phone, for some reason the Lenovo laucher sees as if you've got two times the same app, that's why it dupplicates the icon. According to this video (in Brazilian portuguese)
https://www.youtube.com/watch?v=AqTWneYD0pA
this is a bug that doens't affect the phone's performance, but there is a way to fix it, even if not permanently. This is what you do:
Settings->apps management->all->Lenovo Laucher->Clear Data->ok
This is NOT a permanent fix, for everytime you rebbot your phone, it will continue to see one app in the memory card and one app in the internal phone memory, so it WILL continue to duplicate.
So my solution to that would be:
-Take a look and see what apps are being duplicate and leave them in the phone's internal memory, DO NOT move them to the memory card.
-OR change your laucher to the Google Laucher. No problems found there.
My phone was duplicating some apps I had downloaded, it never duplicated anything that came with the phone, such as calendar, syncIt, shareIt, calculator, nothing like that.
I hope this is helpful! I didn't post it before because I wanted to make sure it worked.