Pre install question

I was wondering with CB before I attempt this I plan to clone Drive C: which would be actively working with its WinXP Operating system and Comodo Backup to Drive D: which has an old OS (which would get wiped out when I perform this action. My question can the Cloning process work on a drive which is operating on the way I want to do it? Any gotchas I should know about?
Thank you in advance.

Cloning can be performed if destination drive (D:) is not in use.
The source drive can be used during cloning operation without any problems.
There aren’t any other gotchas.