I signed up for the free 14-day trial of CCleaner - Professional Edition. I'm trying to wipe an entire drive, but that option is grayed-out. Is that because I only have the free trail edition?
https://www.ccleaner.com/docs/ccleaner/using-ccleaner/wiping-free-disk-space
Entire Drive will erase all of the files on the drive. WARNING, this means the whole of the partition will be erased. The drive will still be formatted, but all data will be erased. For safety reasons, this feature is disabled for the boot drive.
Okay - thank you for that answer. I understand.