By the page: “If you want to use TortoiseCVS on Windows 8 or 10, your best bet is to try out the version maintained by March Hare. ”
I can’t afford the pro version. (https://www.march-hare.com/cvspro/)
Fortunately the TortoiseCVS-1.12.5 is working on my Windows 10 64 bit pc!!
Older downloads: http://www.tortoisecvs.org/download.shtml