Why would you cancel the install half way through, is that something you normally do?
If you don't have the time to install it properly, don't start the process. If you do have the time see it through.
If you think you have made a mistake and can't simply back up to the step you think you messed up, just continue. Most things can be fixed after install. Worst case scenario, you will just have to reinstall.
If you backed out because you were afraid of messing up your windows partition, I highly recommend backing up all your data before you install in the first place.
In what world is that normal?
The world where the vast majority of people don't cancel installing an OS halfway through the process.