How do I upgrade Ubuntu OS from 32 to 64 bit?

Solution 1:

Practically, you cannot upgrade an OS from 32 bit to 64 bit but there is a workaround: Aptik.

• Install Aptik:

  sudo apt-add-repository -y ppa:teejee2008/ppa
  sudo apt-get update
  sudo apt-get install aptik
  

• Run, Aptik.

• Backup all the required data.

• Install new Ubuntu 64 bit.

• Install Aptik.

• Restore everything.

Solution 2:

As far as I know you can upgrade from older to newer versions of Ubuntu, but not from 32 to 64 bit. Even if it were possible, you could face so many unexpected hardware surprises so I would strongly recommend you go for a clean install.

Here's the link for Ubuntu 16.04.2 Desktop 64-bit iso.