Can't Import Lightroom Files Because of Disk Space - Even Though I Changed the Catalog Location

Every single time I try to import photos into Lightroom I get an 'Insufficient space' error for my C drive. I don't get why I'm getting this error - Lightroom is installed on my D drive which has 200+ GB free. It asks me to change my local storage settings - so I change my 'storage location for originals' to my D drive as well and I still get the exact same error. My CC Sync file is ALSO on my D drive. What do I do?