WebCopy is available in both 32bit and 64bit versions, but are no longer installed from the same setup. Please download the specific platform you wish to use from the Cyotek website.
The 32bit version can be used on both 32bit and 64bit operating systems. The 32bit version has a 2GB limit for the amount of information it can hold in memory, which may cause issues trying to large websites.
The 64bit version can only be used on a 64bit operating system. 64bit versions can use more than 2GB of memory, but also use more memory in general.
Secondary support applications may still be 32bit, even when installing the primary 64bit application.