Moving files in lightroom

HELP! Something has happened to my lightroom. My usual workflow is to import all photos into a folder. Then under that folder I create a folder called 'Unedited' and move all photos to here. Then once i've edited them I move the files back to the main folder. For some reason its no longer allowing me to move the files out of the main folder that I've imported the photos under?

Hopefully someone can tell me what i'm doing wrong. I'm using a Mac which I've always done. Not sure if its a lightroom upgrade thats causing me the grief or if ive done something?

Thanks

Kris