Starting with Windows 10 version 1803 a native version of OpenSSH is bundled and installed by default.
If you are using posh-git you'll notice that the
Start-SshAgent command fails with an error:
unable to start ssh-agent service, error :1058 Error connecting to agent: No such file or directory
This is because by default the OpenSSH agent (ssh-agent) service is disabled. To enable it, open an elevated PowerShell window and run:
Set-Service -StartupType Manual ssh-agent
Start-SshAgent will work as it always has, however by default Git (for Windows) will continue to use the bundled OpenSSH package.
This means that you are now running an ssh-agent that Git will not use.
To fix this add the following to the Git config:
[core] sshCommand = C:/WINDOWS/System32/OpenSSH/ssh.exe
I generally use this command to edit the global Git config:
git config --global -e.
Now Git will switch to the Windows supplied OpenSSH implementation, and everything works together nicely.
Update 29-01-2020: Removed quotes from Git config as these are not needed; added git config instructions.