My current OS is Ubuntu 16.04 LTS. I, out of curiosity, installed Elementary Desktop. And then I removed it and got back to Unity.
I installed it using following command:
sudo add-apt-repository ppa:elementary-os/stable
sudo apt-get update
sudo apt-get install elementary-desktop`
and removed it using:
sudo apt-get remove --purge elementary-desktop && sudo apt-get autoremove
Now after reverting back to Unity, when I checked my OS, its still changed to elementary OS.
Following is the text from hardinfo app:
-Version-
Kernel         : Linux 4.4.0-45-generic (i686)
Compiled        : #66-Ubuntu SMP Wed Oct 19 14:12:05 UTC 2016
C Library       : Unknown
Default C Compiler      : GNU C Compiler version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.2) 
Distribution        : elementary OS 0.4 Loki
How can I fix it?
 
    