using diskpart to clean it make the disk unreadable winuae see the disc,but HD toolbox does not see it.
I've seen this happening, too. In this case after CLEAN in DiskPart enter CREATE PART PRIMARY and then DELETE PART. After exiting DiskPart you should remove the card and plug it in again.
You always have to run WinUAE as administrator when working with real harddrives. Leffmann told you how.
