Can't Back up Phone, not enough Space

So recently I've been trying to back up my phone before I upgrade it to the new iOS 8.4, (I currently own a iPhone 5s). Every time I attempt to back up to iTunes, (which is on the latest update) or to iCloud. I get the same error. "There isn't enough space on this computer, please empty recycle bin to clear space." I'm running Windows 8.1 and have a terabyte of free space on my hardrive. Plenty of room for my phone to make a back up. I've googled and done everything that was recommended. Rebooting both phone and laptop, deleting photos and what not. This is a brand new computer so I don't have any previous backups to delete. The only other suggestion is to restore the phone. And I really don't want to restore it without a back up! Help?