recent versions of gpg-agent from Gpg4Win 5 beta (at least since beta345, windows 10) are unable to establish ssh connections with putty. when trying to open an ssh connection, the taskmanager shows that for a brief moment a smartcard daemon is started, but soon after both the smartcard daemon as well as the running gpg-agent are killed. after this failure of public key auth, the remote ssh server switches to another available auth method (e.g., prompt for a password).

using windows' built-in OpenSSH is not affected.