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I've never tried dual booting before. It's always been the feature that I've considered meh... Since my sister wants to use windows and I find elementary OS pretty flexible and easy to use with a beautiful interface. I tried to shrink my Disk D Volume to 120GB and then install it on the unallocated space. I'm clearly new to this kind of thing so I probably sound dumb.It just fails. Doesn't even want to start installing. If anyone can tell me what's the problem and how to do it right I would appreciate it a lot.