koresz

Hi, I have a problem with CCleaner's disc recognition. In my laptop with Windows 10 Creator's update I have an SSD (divided to C and D) and an external HDD (F) connected via USB cable. I want to wipe the free space on the external HDD with several overwrites (3 or 7). But the only option CC offers me is the simple overwrite because it detects my HDD as SSD. When I select 3 or more overwrites the drives just grey out and I cannot check them anymore. Can anybody help me with this?