This is not a true error in the sense that Nmap cannot work. However, having the legacy OpenSSL provider installed will allow the use of legacy crypto that may be needed to fully probe some outdated services and devices. In our Windows builds, the legacy provider is built-in, so the load fails because it is unnecessary. I've added some checks to ensure we only print this warning when the -d option is used (debugging).

I also encountered this problem, does it not affect scanning? thank you

I have also experienced this error when running Zenmap GUI 7.93. This is the output of nmap --version on the command line:

Nmap version 7.93 ( https://nmap.org )
Platform: x86_64-apple-darwin17.7.0
Compiled with: nmap-liblua-5.3.6 openssl-3.0.5 nmap-libssh2-1.10.0 libz-1.2.11 nmap-libpcre-7.6 nmap-libpcap-1.10.1 > > nmap-libdnet-1.12 ipv6
Compiled without:
Available nsock engines: kqueue poll select

I am receiving this error whenever I run an Intense scan in Zenmap.

I don't use -d for debugging, and I still see this error. The scan still runs, but this error always occurs when I run Intense scan. I've tried removing -v to disable verbose output, but I still see the error.

I saw this error today using a copy of zenmap for windows installed today. The command I ran was; nmap -sU -p 47800-47810 --script bacnet-info 192.168.0.4

Solution for macOS.

1. uninstall nmap 7.93

For homebrew nmap

brew uninstall nmap

For dmg nmap

sudo rm -r /Applications/Zenmap.app
sudo rm /usr/local/bin/{ncat,ndiff,nmap,nmap-update,nping}
sudo rm /usr/local/share/man/*/man1/nmap.1
sudo rm /usr/local/share/man/man1/{ncat,ndiff,nping,nmap-update}.1
sudo rm -r /usr/local/share/{nmap,ncat}

2. Install nmap 7.92
   https://nmap.org/dist/nmap-7.92.dmg