Solution 1:

Answer in progress

  1. Run the Python script in /usr/bin/katoolin again

    sudo /usr/bin/katoolin
    
  2. Select 1) Add Kali repositories & Update

  3. Select 3) Remove all kali linux repositories

  4. Run

    sudo apt-get update
    sudo apt-get install -f
    sudo apt-get autoremove
    
  5. Remove the katoolin script

    sudo rm /usr/bin/katoolin
    
  6. Run

    gksu gedit /etc/*release  
    

    Change the file like this (depending on your release):

    DISTRIB_ID=Ubuntu  
    DISTRIB_RELEASE=16.04  
    DISTRIB_CODENAME=Xenial Xerus  
    DISTRIB_DESCRIPTION="Ubuntu 16.04"  
    

    Save and close the file.

  7. Run

    gksu gedit /etc/*issue  
    

    Change the file like this (depending on your release):

    Ubuntu 16.04 \n \l  
    

    Save and close the file.

  8. sudo apt-get install --reinstall software-center