MS Windows Home Server

WHS had been running fine for months and developed file conflicts which I isolated to 2nd HD (although files were still there) so I added a drive to the server (NOT part of main storage however) to backup conlict drive to so that I could remove it. ALL files that were listed as conflicted were deleted. When I try and remove the drive I get the following error ;

"There is not enough room on your WHS to sefely remove this HD.
Try the following to free space on server,
Add another drive,
Turn off folder dupe,
delete unwanted files.

unfortunately the drive I want to remove has 0GB on it and the other 2 drives are only 60% and 71% used, duplication is already off.

I can send anyone a .pdf of screen shots to confirm, any help appreciated

Thanks