Apps Won't Install

I have moved my preference location to a drive that has 1.5 terabytes of free space but when I try to download my apps, there is an error and it tells me there is not enough disk space. I've searched the forums for answers but nothing has worked. I'm not sure why it keeps telling me that there is not enough space even though there are 1.5 terabytes of free space. Why is this happening? and how can I fix it?