'ssh-keygen' is not an internal or external command, nor is it a running program or batch file.

1. Find the ssh-keygen.exe installation directory; (mine is in D: \ git \ Git \ usr \ bin)

2. Configure environment variables: advanced system settings >> environment variables >> system variables;

　　　　　　　　  Find path "for editing, paste the path of ssh-keygen.exe into it

3. Save, it should be OK;

(Win7 and win10 seem to be different when configuring environment variables. The list of win10 has a list, and the end of win7 must be added ";")